Troubleshooting – Basement Sewer Smell

I Can’t Get Rid of the Sewer Smell in My Basement?

This is definitely a question we hear fairly frequently and most times it’s relatively easy to troubleshoot. The very first question you should ask yourself or a potential customer is “do you have a floor drain in your basement?”

If there is a floor drain in the basement and it is unfinished it is likely there to receive condensate water from the furnace. Quite often that is the only water that drain ever receives.

So if there is a floor drain and it’s getting very little use the trap serving the drain may have dried out. If this proves to be the case mix a little bit of Mr. Clean or house hold cleaner that gives off a fresh scent with a gallon or so of water. This will do two things, prime the trap and clean out any nasty water that may have been laying stagnant in the trap.

That brings us to the second question and it definitely ties into the first, is there an ejector pit and pump in the basement? If you have a basement and you have an overhead sewer you should have two pits in your basement. One pit with a sump pump to handle ground water and one pit with an ejector and a sealed cover to take care of ANY waste water. Including condensate water.

It is code to have a gas tight sealed lid and the pit should be vented. We should back up for a second. Because most ejector pits only receive condensate waste, home builders frequently put in sump pumps without a sealed lid.

If you have an ejector pit and it is receiving waste water from a laundry, basement bath, kitchen, etc. and it doesn’t have a sealed lid or vent piping there is a strong possibility that pit is the origin. So if you find this is the culprit these are the things you need to fix the problem.

  • Purchase an ejector pump
  • Purchase an ejector lid with a seal kit. Ejector pits come with two holes; one for the waste discharge and one for the vent. (Try and find a lid that fits your pit. Most times the edge of the pit needs to be modified for the new lid to fit)
  • Seal the ejector pit and install the vent piping and tie-in to a vent line overhead.
  • Not the Ejector Pump and not a Floor Drain?

So you’ve checked those two things out and there is still a smell in your basement? The next question we would ask is “Are there any plumbing fixtures is the basement?” For example, a laundry room or a basement bath. These groups of fixtures should be vented like any other, we’ve seen plenty of basements vented into the wall and that vent ties into nothing.

The open vent can be the cause if the sewer smell. We have also seen vents for bathrooms and kitchens on the main floors not tied-in, this sewer gas smell can make it’s way to the basement. If the smell can’t be tied to a basement fixture then a peppermint test can be performed.

If it is none of the above you may have a broken sewer line. How would you know or how should someone diagnose the problem? If a sewer line is broken the brackish water is leaching into the ground somewhere. What receives ground water from the area around the foundation? The drain tile system, the water from the drain tile system makes it’s way to the sump pit. That is usually where you will smell the sewer gas.

How to Diagnose the Sewer Line Being Broken.

You have to purchase leak tracing dye. Has anyone here seen pictures of the way the City of Chicago dyes the Chicago River green on St. Patrick’s day? They are using a biodegradable fluorescent tracing dye.

Trace-A-Leak makes dyes in myriad colors. Anyway….the plumbing tech or homeowner should fill up a bathtub and put some of the tablet in the tub or dump some of the tablets in a toilet. Release the water from the tub or begin flushing the toilet. If there is a leak the dyed water will leech its way into the soil and make its way back to the sump pit. This may take some time but it isn’t uncommon.

As always we hope you enjoyed the article and if there is anything our readership would like to add feel free to leave a comment. They are always welcome.

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  1. Jim Dow says

    I am reading my tail off. Your answer is the best I have seen so far. I have a 4 flat with a full basement. There is a laundry room where there is a sump pit for the building 4″ corrugated building tile. The sump is submersible type, no vent, steel – unsealed lid, discharges to outside through wall just above the foundation.
    sitting next to this pit is the ejector pit. the laundry tub and floor drain empty into this pit where it is then pumped to the overhead sanitary sewer. There is a approximate 1″ pipe between the 2 pits. The ejector pit is also covered with a steel lid which is not sealed. No vent pipe for this pit either.
    The sewer gas smell seams to be coming from the sump pit. The building pipe is above the water line under dry conditions. I do not have any drain issues from the apartment units in the building. The smell is not constant. It is at its worst when it has not rained for a while (like today). I have 2 additional identical buildings on the same city block, configured the same way and they are fine.
    With the cost of plumbers and so many that just guess I do not want to pay big bucks for the unknowing to become knowing on my dime.
    Seal and vent the pits? Is it ok to seal and vent? I have never seen sump pits sealed let alone vented.
    Should I have them camera the building to city sewer line looking for a break?
    Thank You for your time and knowledge,

    • says

      Well that was an excellent explanation Jim and you are funny too. Sometimes you fly blind, the only way is to do research but I certainly see your point. Let’s see if we can get to the bottom of this for you. Let’s address the sump pit & ejector pit. Because there is a connecting pipe between the two pits you would have to seal both of them to seal off any sewer gas odor. if you do decide to do that I’d recommend venting as well. I know its rare to have a dangerous sewer condition in a ejector pit but why take a chance.

      An ejector pit should never be connected to a sump pit. If that seems like a little much than I suggest you find a way to block off one pit from the other, seal and vent the lid on the ejector pit.

      I know you mention the smell seems to be coming from the sump pit. That could be the gas moving over from the ejector pit to the sump pit or you could have a sewer break and the brackish water is finding it’s way back to the drain tile and that is making it’s way to the sump pit hence the smell. Have you checked any floor drains nearby for trap seal evaporation?

      Here’s how I would handle video taping. I love sewer cameras they are great diagnostic tools and the new models are in HD so floaters take on extra special detail. lol However sometimes breaks are difficult to see, I would rather know there is a break and then try to find it. Have an experienced plumber dye test first.

      Hope that helps. Feel free to email us @ if you want to discuss further.


      • Jenny says

        Hi, Thanks very much for the information on ‘sewer smell in the basement’. I have a similar problem, though the smell is a musty, mildew smell. The basement is in an old property in Italy. There is a ‘well’ under the floor to take up ground water and when the level rises a pump clicks on and pumps it out. There is always a shallow level of water in this ‘well’. It is sealed with a double seal man hole cover, which has been removed frequently recently as the pump broke and water rose up into the basement. Since being fixed and the cover replaced the, always present, smell is much stronger. Should I be groutting over the edges of the cover? If so, I want a sealant which will dry out completely (damp is a problem in the basement) and be easy to pick out when I next have a problem with the pump. Also there is no de humidifier in the basement. I have brought a portable one, and there is an extraction fan which clicks on for 1 hour a day. But dampness remains a challenge. Any tips on that one as well? thanks

        • the plumbing info says

          Mildew smell is by and large a product of standing water. A dehumidifier will certainly help the problem. Is the sump pump on top of a platform of some kind? If the pump isn’t on the bottom of the pit you will always have standing water and over time that water will get funky. Hope that helps.


  2. Susan says

    Ever since I had new pumps and parts installed in my dual chamber septic tank I have had smells in the basement that seem timed to the pumping of the septic tank-about every 150 gallons.
    I read online that the chamber with the pumps should be vented out the lid. We never had this before and had no problem. Could this be our problem now?

  3. Christine Bullen says

    We have a sewer clean out pit in our basement and it has a musty, damp odor. It is under the floor in a finished room, with a lid that comes off in case of servicing. Is there a way to get rid of the odor?

    • the plumbing info says

      If this pit takes drainage from something other than ground water it is technically a sewage ejector. You say sewer clean out so I’m assuming it is an ejector pit. If so it should be vented with a sealed lid. That will take of your odor problems.


  4. Bob Rivera says

    This is the best explanation of sump pump/ejector pumps I have come across.

    I have a similar issue with sewer order. The odor is intermittent and occasionally surfaces when we run the washing machine.

    We have an ejector pump that is sealed (hard plastic) and the smell is very strong along the cover. How can I check whether the plumping (washer, sink etc) drain to this pump?

    There are several rubber gaskets on the vent pipe coming out through the cover lid. Is there an inspection process to test whether they are still sealing appropriately (other than an odor check)?

    Any other inspection tips would be helpful.


    • the plumbing info says

      Hey Bob thanks for the compliment we certainly appreciate it. This is definitely something you can check yourself. I’ll address the questions as you wrote them.

      Question : “How can I check whether the plumbing (washer, sink etc.) drain to this pump?”
      Answer : Unbolt the lid and run the sink and or washer. You should be able to hear the water running into the pit, then when the pit fills up the pump should cycle. You could just run the water and put your hand on the discharge pipe and wait for the pump to cycle (you’ll feel/hear the pump cycle) but it sounds like you may have a bad gasket or gaskets so you’re most likely going to have to unbolt the cover anyway.

      Question : Is there an inspection process to test whether the gaskets are still sealing properly?
      Answer : Honestly, I’m not going to make this any more difficult than it has to be. You are doing the inspection process already. If you are smelling sewer gases near the ejector pit you have one of three problems:

      #1. Your gasket around the perimeter of the pit is pinched or more likely dry rotted and needs replacing.
      #2. Your gaskets sealing the discharge piping and/or vent piping is pinched or more likely dry rotted and needs replacing.
      #3. You have a crack in your vent piping and sewer gases are escaping. This is the least likely of the three.

      If it’s a gasket issue, measure the diameter of the pit or the piping and call your local plumbing supply house with those dimensions and they will help you out.

      Hope that helps, let us know if you need any more help.


      • Bob Rivera says

        Thank you for the follow up reply.

        Upon further inspection of the ejector pump cover I noticed the basin bin, which is about 22in diameter, does not sit flush to the concrete. About 2/3 of the bin is inside the basement slab while the other 1/3 is on top of the concrete slab creating a 1/2 to 3/4 inch gap.

        The gapped area is where the odor is the strongest and even without the odor currently noticeable in the room if I can detect some odor in the gapped area

        Should the basin bin sit inside the concrete slab or on top?
        Can I apply silicone to seal the gapped area?


      • Bob Rivera says

        Let me give a bit more detail on our setup and troubleshooting steps we have conducted.

        There is a floor drain in the basement with a vent pipe. The floor drain connects to the ejector pump pit. The ejector pump pit does not have its own venting pipe so I’m assuming it uses the floor drain vent pipe.

        The only water that uses the floor drain is the HVAC (AC condensation and Aprilaire for the heat) and the water softener.

        Note: The odor is very strong after the water softener runs its discharge cycle and drains into the floor drain. The odor clears out after several hours, less time when open the basement window. The HVAC draining does not provide enough water to have the ejector pump engage.

        I placed my nose by the HVAC vents and I can detect t (slightly) the same odor we get in the basement.

        I removed the pit cover (there was a broken screw). I replaced the broken screw and gasket. Even after I tighten the screws the pit cover moves slightly when I push it down. Not sure it that is its own issue.

        Although we conducted these procedures, after the softener discharged we still had the odor.

        Any additional advice before I call in a plumber?

        Any information is appreciated.


        • the plumbing info says

          Huh? Thanks again Bob for coming to us with your problem. You’re making us put our thinking caps on. I have two questions for you, you are positive there is nothing else draining into that pit? No laundry tub? Is the smell coming out of the pit a sewage smell or a sulfur smell like rotten eggs? Let me give you my thoughts assuming there is nothing else but the condensate, softener and the floor drain. I will say my initial response is to tell you that pit needs it’s own vent. There is a possibility that when the ejector discharges the negative pressure pulls the water from the trap seal of the floor drain, but the smell doesn’t seem to be coming from the drain.

          If nothing else is going into the ejector pit then there is something else going on in that pit. My first guess is that somehow you have brackish water making it’s way into pit. Softener water can have a sulfur smell when hydrogen sulfides are present in the potable water. You can use dye testing on your house sewer to see if the dye makes it’s way back into the pit but that is a long shot if that pit is really only taking water from the above. Just to clarify, dye testing is very affective when the smell is coming from the sump pit. If there was a sewer line break, the brackish water will seep into the drain tile system and eventually make it’s way back to the sump pit. So if you dyed the waster water that dye would show up in the sump pit.

          Let me give you one more piece of advice before you call the plumber. You can try using a can of Bioclean. It uses natural enzymes to break down organic material. It works very well in ejector pits. I’m going to leave you an email. I’ll sell you a can if you want. They aren’t up here yet but I’ll send you a paypal invoice.

          BTW The cover should fit tight to the pit.


          • Bob Rivera says

            Sorry for the lateness of the reply, I thought I submitted a follow up.

            After much trouble shooting and cover gasket replacement, I decided the plastic cover had too much play and may have lost its integrity through the years.

            I applied a bead of silicone between the cover and the rim of the pit and I have success, no more odor.

            Thanks for all your help


          • the plumbing info says

            Hey Bob I’m glad we could help, that’s why we’re here. Please let your friends and family know about for all their plumbing issues. Don’t be a stranger.


  5. a says

    my basement smells strongly of sewer gas after i finish doing laundry…the smell usually doesn’t go away for a couple day after, and my plumber says he doesn’t know what the problem is…any suggestions? we are desperate for answers, we have a bedroom down there!!

    • the plumbing info says

      Hello and thanks for the question. Before I can answer yours I need for you to answer a few of mine.

      Do you have a basement with a sump pump or an ejector pump?

      Do you have a floor drain in your basement?

      If you answer those for me I can trouble shoot for you. Thanks.


  6. Harmonie says

    Hello. I am in search of answers. I too have a sewer smell in my basement. I thought it was just dirty drains so I put drano down the shower and the sink. No luck. The stink still comes back. I read your questions to try and trouble shoot and the only one I can answer is that I have a floor drain in my basement. It is covered with carpet – which makes me think “what’s the point?” When I put my nose to where the drain is I don’t smell anything. It is more like it is coming from the heating/cooling vents in the ceiling. We had a leak in the upstairs bathroom galvinized pipe under the sink had rotted out. The leak dripped down of coure into the basement through a light fixture. We had that fixed, however the smell continues. Could I have some sort of sewer related leak in my basement ceiling? It’s all drywalled up so I can’t see the pipes. Ahh! DO you have any suggestions. Can a plumber come out and diagnose the problem? Can a camera be run through the pipes to look for leaks?
    Any information would be appreciated.

    • the plumbing info says

      O.K. sorry for the delay in my response. My first question to you would be do you have an ejector pit in the basement? If not I think you may have a leak in the ceiling or maybe a broken vent pipe somewhere. You can use a camera to inspect waste, vent and storm piping but it really isn’t practical for inspecting water lines. You are better off taking some ceiling down to visually inspect the piping. Galvanized piping has gone out of favor for use on water piping because it oxidizes and deteriorates over time. You telling me that you have galvanized piping puts the house at over 30 years old. Maybe someone used it later than that but I’m guessing not. The piping could have pin holes leaks in multiple places so a skilled plumbing technician is a must for this issue. Let me know how I can help.


  7. Laura Mac says

    I too have a sewer smell in the basement. There is a floor drain for overflow from furnace. There is no sump pump, ejector pump or any other openings or holes in the floor. I tried bleach and water to prime and clean the trap. This seemed to work for a short time. Recently people moved into the house(it was vacant) and I had them do the water and bleach also. It only worked for a day. The home is on a high elevation, and there is very little water from the furnace. It was built in the fifties. Did they not use S traps then? Can we just seal the drain?

    • the plumbing info says

      Hi Laura, they actually did use S traps back in the fifties. It is possible that the drain isn’t trapped, that would certainly cause the odor issue you talk about. I have a question for you, can you see water laying in the bottom of the drain? If you can the drain is likely trapped. Are you sure the odor is coming from the drain? There could be an open vent line somewhere in the basement. The only other suggestion I have would be that you may have a broken sewer somewhere under the floor and the brackish water is making its way back to the drain somehow. Fill me in and maybe I can give you a better diagnosis.


  8. says

    Wow definatly alot of very good info on this forum. Hopefully the problem I have is somehting that is easy to fix.

    I full bath was installed into my basement with an ejector pump to push out the water from tub sink and toilet into the regular plubing line. nothing else should be going into that ejector pump however when ever we use the bathroom upstairs the smell of sewer gas overwhelms the house. Our central air/heating system is inside the basement as well and when the basement stinks up the whole house gets the circulation. Its a gas cause its the kind of smell that sticks the back of you throat. the smell is coming from the area where the pump is at but that area is also where the house main vent pipe is as well I dont know where exactly the smell is coming from, if from the vent or the pump. How could I fix this. It seems to be getting worse and worse. I have tried flushing clorox and lyson down the drains to see if it can make the smell decrease but it doesnt seem to be working. I am about to call the plumber but hoping from some guidance from here first!

    • the plumbing info says

      O.K. let me give you my initial thoughts and then we can move to diagnosing the issue. Is the cover on your ejector sealed and bolted down? Is the pit vented? If it isn’t sealed and bolted and you don’t have a vent that is very likely your problem. The sewer gas is escaping the pit, the odor is getting into your air returns and it’s dispersing that pleasant smell throughout the house.

      If you have a sealed cover and it’s vented then there are some other issues. The first thing I would do is to check the vent piping for any cracks.

      If after you’re finished troubleshooting the ejector pit and pump and you still have an odor issue you may have a cracked or open vent. Here is how you can test to see if you have a vent issue. Do a peppermint test. Close all the windows in your house and make sure all traps are sealed, floor drains, toilets, lavatories, kitchen sink traps, etc. Locate the main vent going out of the roof of your home. Go on top of the roof (Please use the utmost care when climbing on a roof, make sure to where a safety harness and tie yourself to something sturdy in case you slip (Or better yet call a plumbing professional to do the test for you) put a bottle of peppermint oil in the main vent stack and seal off the top. It is very difficult for the individual introducing the peppermint to the vent system not to smell the peppermint so you need someone else to be inside the house to check for the peppermint smell. Start in the basement and work your way up into the house. If you catch the peppermint odor in the basement or somewhere else in the house chances are you have an open or cracked vent.

      Please follow up with us and if you need further assistance leave you questions here.


  9. Amanda from Denver says

    Ok, so Ive read and re-read all the posts and comments and advice. (by the way, this is by far the best site with all the information given) Im so lost on what to do. Back in November the water board came over (because I thought I had a leak, no leak was found) (( there was NO smell then)) and told me that the water softener we had in the boiler room was a waste of time so we switched it off. Not since then but around that time we have had a rotten egg smell in our basement. First we thought it was the bathroom down there but Ive run water in the traps (?) is that right.. traps being the toilet u bend and sink u bend etc etc. That didn’t do anything. I then filled the sump pump with water/bleach and let it run through a couple of times, thinking the water might be stagnant, that didn’t help. I then called a plumber who told be he has no idea what it is but he thought it might be the sump pump and to put more bleach down it. So I put a bottle down it.. it sort of helped for a day.. then its come back. I then read that we should check our floor drain and pour water down it as it might be low. We did that (even though the water level wasn’t low) and miracle of all miracles.. it worked….. for a day.. it was heaven to be in a house that didn’t smell of sewage. Then it came back! The next day! It seems to get worse.. much much much worse when I run the washing machine and Ive read somewhere that water might be sucked out of somewhere with the force of the washing machine etc etc creating sewer gas smells to come through but I have no idea where to look or what to do with it. I have also read that it might be the condensation line running from the AC/furnace (?) unit and it might be cracked somewhere and sucking all the foul air through the house? Then I just read about doing the peppermint test which can tell if its a cracked vent.
    So, I have no idea where to start, which one to check first and how to do it.
    The floor drain has a white PVC pipe going to it and also 2 little tubes going to it. None are in the water of the drain. I can’t see where the little tubes are coming from as they go behind the boiler and there is no room to see where they are actually attached to. (the water softener unit maybe?)
    We don’t really have enough money to keep calling plumbers out for them to tell us its the sump pump. However, when we open the lid of the sump pump there is definitely a smell coming from it. (it hasn’t run since the summer by itself) But I don’t think its the same smell that we smell coming from the vents and in the basement.
    What on earth can it be? What can I do to check the options I’ve read about and not get too freaked out that it might be a really really huge problem. I can send a pic of the floor drain if that helps explain?
    Please please help.
    Thank you in anticipation

    Stinky Basement lady

    • the plumbing info says

      Dear Amanda (a.k.a Stinky Basement Lady)

      First of all thank you for reading and for the kind words. We will always attempt to give you the very best and most accurate plumbing information and advice on the internet. I’ve got a few questions for you regarding your issues.

      #1) What is the “water board”? Other than a now banned CIA torture technique. Am I to assume this is a municipal service? Again maybe I know the service by a different name. Did they give you a reason why they thought the softener was a “waste of time”? Do you have hard water issues? If so the softener is not a waste of time.

      #2) What kind of odor do you have? You’ve said a “rotten egg smell” and then you mention “sewage” smell. Although both can be caused by decay related to sewage a strong rotten egg smell and a sewage smell are distinctly different. As I’ve said in some of the previous posts rotten egg smell is sulfur or hydrogen sulfide.

      #3) Do you have a septic field for your waste removal?

      #4) The smell started after the “water board” told you to turn off your water softener?

      If you could answer those questions it would help me out quite a bit. Just so you know, I have an idea as to the cause but before I give you an opinion I’d like some clarification.


      If you could answer those questions for me that would

  10. Amanda from Denver says

    Hi there, Thank you for your quick response. Its greatly appreciated.
    #1. The ‘water board’ is a term we use in the UK,(I’m originally from there) I revert back to my native tongue when I dont know what else to write, no torture required.. the smell does it for us.
    #2. It is a sewage smell, not rotten egg.
    #3. No septic field, we have 2 run offs to the road. (?)
    #4. We turned off the water softener after the ‘Water board’ told us it was a waste of time and energy, that we have the best water in the country (biased I know but we agree) as we have no lime scale etc etc. The smell started around that time. Since then we switched it back on a few weeks ago and nothing changed. So, we switched it back off again.

    I ran the washing machine 3 times today and the smell was hideous. Overwhelming. I cant invite anyone round as its so embarrassing and my kids are starting to think this is normal.
    The sump pump and drain are in the same room so I cant tell if its coming from one or the other. I lift the sump pump lid off (its not secure, just a trash lid laid over it) ((however, we have never smelled it in the 3 years we have lived here)) and it smells stagnant but the drain area definitely smells like a sewer.
    I was even tempted to get on the roof and check for a blockage in the vents up there.
    Again, waiting in anticipation… Please please please tell me its going to be an easy fix.

    • the plumbing info says

      Haha, I love it “native tongue”. Last question I promise. What is running into that sump pit? i.e. laundry, condensate waste, ground water, maybe a basement bath or non of the above? This can only be one of three issues. If you have laundry drainage or some kind of waste running into the pit (laundry waste can get funky if is sits on a pit because it’s tough to remove all the lint not to mention the soap) you need to get a gas tight cover and the pit needs venting. If nothing else is going into the pit and you are confident the odor or odour in your native tongue is coming from the pit than somehow sewage is getting to the pit.

      The most common way sewage gets to a sump pit is when a house has a break in their house sewer. You can have a sewer line break and not experience a back-up….yet. It will happen eventually but you could go years. In order to find out if this is happening you have to dye your waste water with florescent dye. You put the dye in your toilets and bathtubs or kitchen sink and you run your water. You have to have two people working on it because one has to watch the sump pit. If you have a breach or break in your sewer line the dye will make it back to the sump pit. If that happens you know how the smell is emanating from the pit. If that doesn’t solve your problem then there is a broken vent somewhere.

      It is possible to have a clogged vent but it is unlikely that the issue would result in sewer smell in your basement. You would have drainage issues that would go along with the odor.

      Hope this helps you. If you think you need to get a plumber to your house let me do a little magic. I think I can get someone to help you out. Let me know. Do you live in Denver?


  11. Amanda from Denver says

    Hi there, thanks for all the info,

    There is only ground water going to the sump pit, nothing else. My husband and I went down there last night as it smelt soooo bad and double checked the sump pit, it definitely is not the place where it is smelling. my husband put his head way down there and confirmed it was not the same smell as we have in our basement. So, is it still worth doing the waste water dye kit? The sump pump has not run (or filled up) on its own since the summer.
    Do you think it might be a broken vent then? If so, is there any way I could check for it myself? etc etc
    I have a feeling we are getting to the core of the problem and have a hope that this might be resolved??!!!Thank you.

    Your magic… what would that entail, yes we live in littleton, Denver.

    • the plumbing info says

      I’m going to ask one more stupid question. Where does the basement waste water go? Where does the discharge from your floor drain go? Does your house drain run under your basement floor or does it run over head? If you’ve given the sump pit the whiff test I don’t think it’s necessary for a dye test. It’s very possible you have a broken vent somewhere and you need to do a peppermint test or you could have a vent blockage. Answer those questions for me and we’ll move on to the next phase.


  12. Amanda from Denver says

    The washing machine dumps into the sewer line but I think it is above the basement floor. There is only one pipe, the main sewer line, that goes under the basement floor. I would guess the washing machine waste goes under the floor from the back porch to about the oven then joins the sewer line directly below. I really don’t think it is coming directly from the floor drain, I can see water in the drain and it doesn’t smell like the source. If it wasn’t trapped, it would have smelled long before now? One of the plumbing shows (Holmes I think) said that basement traps are not gravity traps (like a sink and thus easy to fill) and only last a certain period of time? May need replaced?

    I also noticed today that I didnt run the washing machine but the furnace kicked on it smelled again. Puzzling? Im guess there must be a smell down there and either the washing machine and/or furnace pulls the smell up? I can try taking a picture this evening but I really dont know what Im taking a picture of? Let me see how my photographic skills are.
    What Im getting ocnfused about is if it wasnt/isnt vented then why havent we had this prolem before?


    • the plumbing info says

      Truthfully just because you had no smell before has little to do with you having it now. We have traced down open vent in homes that have no smells for 15 years and because of a clogged vents or a change in home stasis due to settling and such the sewer smell rears it’s ugly head. Stay tuned.


  13. PRE says

    My basement has an ejector pump. Not sure it has sealed lid or not. It does not smell all the time — on an average once a week or so. We hardly use bathroom in the basement. It puzzles me. If there is a problem, should n’t it smell all the time?


    • the plumbing info says

      Hello and thanks for finding and reading. We certainly appreciate it. The very first thing you should do is see if the lid is sealed. An ejector pump should always have a sealed lid, especially if it’s taking some waste. Even though you only use the bathroom occasionally. The pump doesn’t remove every bit of sewage, so as it sits…….you get the picture. To answer your question “If there is a problem shouldn’t or wouldn’t it smell all the time?” There may be no problem other than getting a sealed cover, if it isn’t sealed and you’re getting intermittent sewer gases it may simply be the air pressure in your house is changing sucking the sewer gas smell into the atmosphere of the house.

      Check and see if you’re pit is sealed. If it is please post again and I’ll be happy to walk you through trouble shooting the issue.


  14. Howard says

    I have been reading your forum (and others) and hopefully looking for a solution to my problem.

    Here goes:

    First the house was built in 1978, all pipes appear to be PVC. The septic system is new (2007) all HVAC is new (2008) and this is the first year we have ever had this problem.

    Now the problem – everyday, following our morning showers (2) we have a smell that permeates our house – like a dead animal. There is also a corner of the basement that has a musty, sewer like smell(approximately 25 feet down wall from where the pipe goes out to the septic) which gets worse after the showers.

    After much investigation (1st plumber) we found that there were two dead mice decomposing under the waste pipe draining from the shower (in a section of drywall that finishes the basement). These were removed along with all debris from their nests and droppings. We also visually checked all lines that we could (those not covered by drywall) and found everything is in good order. All clean-out traps were checked as well.

    We thought this would be the answer, but no – the smell persists.

    We then went to plan B and the second plumber entered the scene. We again visually checked all lines/connections to no avail. Next step was the smoke test. The plumber ran the smoke test for about an hour – we checked everything possible and found nothing. No breaks, leaks, etc. After 3 hours the plumber gave up.

    The smell persists.

    As a follow-up I have thoroughly vacuumed every nook and cranny that I can reach. I have poured bleach into the ground traps and checked the sump (which is in the opposite corner of the basement from the smell (approximately 200′). The sump and ground traps have absolutely no odor of any kind. I have run water in all sinks, tubs and showers. No help.

    Again, the smell only occurs when we run the shower (hot water). Running the washing machine, dishwasher, sinks, etc generates no odor. I have looked under and in the hot water heater. Checked under the furnaces too. Nothing – just the persistent smell (I also checked outside along the basement wall to see if there were any visible dead animals – nothing). By the end of the day, the smell fades and is not noticeable – until the next morning shower.

    Bottom line is that I have reached the end of the line and have no idea what to do next to solve this problem – help, please!

    • the plumbing info says

      @ Howard, first of all thanks for finding us, we’ll figure this out. This is going to take some real problem solving. I have one question for you, is that shower trapped and vented properly? Because the issue is so isolated my first thought would be to see if maybe that shower has no vent and no trap. I’m emailing you my phone number so we can go over it in more depth.

  15. Howard says

    Yes. This was checked and verified by both plumbers.

    BTW, there appears to be something funky with your web site. All links keep taking you back to the home page and not the blog. I had to circle around via Google/cached entries to get get back to you.

    • the plumbing info says

      @Howard Please leave me an email address or send me an email to

      With regards to the website, my website guys are doing some maintenance to speed things up. Unfortunately its not a couple hour fix. Please keep trying. We will figure this out.


      • the plumbing info says

        Thanks for the email Howard. Here are the final questions I have for you before we go trolling for an expert in your area that can get acquainted with the issue. So here goes.

        1) Have you tried the hot water on any other fixture the first thing in the morning? If not, please try.

        2) Are we to assume the odor is only noticeable when he uses the hot water??

        3) When you turn on the hot water in the shower do you notice any discoloration in the water that eventually disappears after the shower is running.

        4) Have the plumbers mentioned doing a test on the plumbing waste system with peppermint extract?

        5) Has your septic tank been cleaned recently?

        6) Has a sewer camera been inserted into the waste piping verifying everything is “OK”?

        7) Has any plumbing remodeling been done recently and if there has was it done over or near where the smell is noticed?

        8) How old is the domestic water heater?

        Before I’d do anything else I’d try the peppermint test.


  16. Howard says

    1) Have you tried the hot water on any other fixture the first thing in the morning? If not, please try.

    Ans: We’ve run other fixtures, but did not notice anything.

    2) Are we to assume the odor is only noticeable when he uses the hot water??

    Ans: Yes.

    3) When you turn on the hot water in the shower do you notice any discoloration in the water that eventually disappears after the shower is running.

    Ans: No, everything looks OK.

    4) Have the plumbers mentioned doing a test on the plumbing waste system with peppermint extract?

    Ans: No

    5) Has your septic tank been cleaned recently?

    Ans: Yes, one year ago. Only 2 people in the house not a lot of use.

    6) Has a sewer camera been inserted into the waste piping verifying everything is “OK”?

    Ans: No

    7) Has any plumbing remodeling been done recently and if there has was it done over or near where the smell is noticed?

    Ans: No

    8) How old is the domestic water heater?

    Ans: 3 years old

  17. Howard says

    Sorry I haven’t gotten back to you, but in the interim I have solved the problem. The solution, to me, is somewhat bizarre and perhaps it will be useful to others.

    As you will recall from my original post, the odor only occurred when we took showers in our master bath. Running hot water anywhere else in the house did not trigger the smell. Upon investigation, following several hundred dollars with plumbers, I found that the only thing different about the waste line in this section of the house was some insulation wrapped around the waste line leading from the master bath – exactly at the site where the smell was strongest.

    Simple solution – remove the insulation, take showers, see the result.

    Bottom line – the odor is gone and has not returned since I removed the insulation.

    Upon inspection, the insulation showed no mold, mildew or any kind of discoloration that would indicate a leak (ditto the surrounding area and the pipe itself). Smelling the insulation, there was no odor of any kind. So I have no idea what the source of the problem within the insulation may be, but it is gone so I don’t really care.

    As I said, this was a very strange situation which is now fortunately resolved.

    Hope this information is of use to you and your readers although it is not a plumbing problem.

    • the plumbing info says

      Hey Howard thanks for getting back to us. I was beginning to worry. I’m glad you solved your issue. If you ever have any other plumbing problems please don’t hesitate to contact us.


  18. Ron says

    Let me begin by saying Great Site!

    I leaning towards the smell in my basement coming from a poorly installed 2nd shower which may have been for a basement apartment which I plan on removing. What are the necesarry steps to remove the shower?

    It is tied into the main waste drain but either not vented and/or no P-trap installed and hence the bad sewer smell.

    Any advice on how to go about successfully removing the pipe work in the shower would be great.

    • the plumbing info says

      Hey thanks for the compliment I appreciate it very much. I can help you with your issue.

      Is the water piping exposed? The very first thing you need to do is shut the water off. Quite often when a plumber installs a basement bath they also install shut off valves so they can isolate that bath to facilitate any future work. So if you have shut off valves turn them to the closed position. If your house is not equipped with isolation valves you’ll have to find the valve serving the whole house. You need to drain down the piping serving the bath and make sure you have a positive shutdown. Meaning the valves should hold the water back with no slight trickle of water. It is very difficult to make any kinda of repairs on copper water piping when there is water going through it. Once you get the water shut off take a look at where the water piping leads. You need to cut and cap the pipe where it connects to the main. If there are isolation valves cut the water piping right before the valves. For this kind of repair/alteration look at Sharkbite fittings from Cash Acme. You should be able to do the whole thing without lighting a torch.

      With regards to the waste piping, remove the shower base. Take newspaper, crumple up and stuff it into the drain line. Cover with concrete and finish. If you wish to reuse that waste line mark it with spray paint and you can just knock out the cement to make your connections in the future.

      Hope that helps. Let me know if you need anymore info.


  19. Heather says

    I’m wondering if you can give some direction. We have a 1950’s era home. The basement has been fully finished. There is a “floor drain”, or rather a pipe in a hole in the floor — the pipe has a loose fitting metal cap in the laundry room. I can visually see no sign of a sump pump, or ejector pit as you discuss.

    After we moved into our home 5 years ago, the floor drain backed up several times with brackish water, flooding the laundry room with 1/8-1/4 inch water. We started treating all of our drains with liquid plumber every 4-6 months, and it the overflow problem went away. Frequently now, we have brackish standing water in the floor “drain”, or whatever that pipe is. The water seems to be water from the laundry room and possibly even kitchen waste. When we run a couple loads of laundry, two of us take showers, and/or run the dishwasher, the “drain” blurps. There are nasty rust colored stains on the flooring surrounding the “drain.” It stinks in the laundry room as a result of the nastiness. Do you have a suggestion for me as to what I am looking at, how we can treat the problem?

    Thank you!

    • the plumbing info says

      Hi Heather thanks for finding us and I’d be glad to answer your question. You don’t have a overhead sewer, your waste piping drains down to it’s lowest point which is under your basement floor and makes its way to the city sewer. The reason you are getting brackish water coming up in that floor drain is because you have a partial blockage somewhere after that drain. The liquid plumber was treating the blockage to some degree but now that waste line servicing the floor drain needs to rodded asap. I never tell people that can’t do it themselves but this is probably one of those occasions where you need a plumbing professional. It could be grease, it could be tree roots and only someone with some experience can get it done right. Let me know how it goes. If you need any help picking a contractor let me know.


  20. Brian Huey says

    I seem to be having an issue related to this forum and would appreciate any advice.

    Background: In my basement, I have an ejector pit (with pump) and a sump pump. The ejector pit is located right behind my furnace. We have a bathroom in the basement that is used frequently and and wash machine that all drains into the ejector pit. Furnace/air conditioner condensation also drains in the ejector pit.

    Problem: I get a sewer smell when:

    1. We use fireplace in basement.
    2. We use airconditioner
    3. We do multiple loads of laundry in one day.

    I suspect a vacuum is being created in the basement when either the fireplace is burning and sucking heat up the chimney and when the air conditioner is on…the smell seems to be coming from behind the furnace from the pit itself. I recently changed my ejector pump, and the pit is not sealed. I suspect this will solve my problems. The house was built in the eighties, and the pit is not in the greatest shape. the lid is rusty. I am rambling….any advice would be appreciated!


    • the plumbing info says

      Thanks for the questions, we appreciate all of them but I have to say on this one you answered it yourself. An ejector pit should always be sealed and with the amount fixtures draining into it it’s an absolute must. Go to your local plumbing supply house and get a gas tight ejector pump lid.

      The only thing I would ask to expand upon this problem would be “is the pit vented?” It should be.

      Hope this helps a bit. If you have anything to add or clarify please don’t hesitate to ask. If you aren’t sure how to seal a lid, let me know I’ll post a video of it.

      • Brian Huey says

        Thanks….the pit is vented.
        Would it be too much trouble to post the video? I would appreciate it.

        Great site! Thanks for all of the useful advice.


        • the plumbing info says

          O.K. Brian give me a few days and we will get a video showing how to seal an ejector lid.


  21. Jewel says

    Interesting situation. I had a very bad sewer type of smell in a room on the ground floor of my house. Had a plumber come check it out, he ran a camera through the trap in the basement. He told me that the pipes were separating and essentially falling apart, leaving the water to settle under the concrete.

    Now, once he left, the smell eventually (within an hour or so) disappeared. It’s been gone for days now and I have no clue as to what was wrong in the first place. Is it possible that there was a blockage that the camera cleared out?

    • the plumbing info says

      @Jewel that could be the case. We have certainly pushed blockages with the sewer camera however we usually see the blockage while we are pushing. There is no doubt that a separation in the piping could cause the odor you’re detecting. I’ve got a real simple question for you, did the plumber run water down the trap before or after the camera work? If so the trap may have been dried out or partially dried out and when he ran the water he filled the trap and now it’s working as it should.


  22. Jewel says

    No, he did not run any water down the trap before or after. However… even though the smell is not permeating the room like it was before, I have noticed that it is still there, faintly. The closer you get to the floor, the more you can smell it. Guess it’s still a problem after all! It’s interesting that it went away though.

  23. Marcus Lee says

    Thank you for the very helpful information on this website.

    We have a bad smell coming from the unfinished part of our basement. It actually smells like its coming from the ejector pit, however its not being used. There is a sump in this room next to the HVAC. It receives condensate waste via a pvc pipe on the floor. About 2 feet away from the sump is an ejector pit with is not currently being used at this point because the bath room is unfinished with a 3 piece roughin that will drain into the ejector pit when the bath is finished.

    This is a new construction, we moved in about a month ago and notice the smell only days after moving in. We were told that water may have been left in the ejector pit and needed to be pumped out. of course that did not work. Then we were told that mud may have entered the roughin pipes during construction and were flushed. That has not worked either.

    This area is directly below the laundry room and the smell is worse when we are washing cloths. The smell is being carried throughout the entire house when the air is on.

    Any insight would be greatly appreciated!!


    • the plumbing info says

      Sorry for the delay Marcus. As always thanks for the correspondence. Here are some questions for you that may help in leading you to a solution.

      1) Is there a floor drain in the basement? If so the trap seal may have dried out. This drain should discharge into the ejector pit but test it out.

      2) The condensate discharge should go into the ejector pit not the sump. I realize this is only condensate drainage but it can get funky if your sump pit isn’t evacuating.

      3) Mud in the waste lines should not smell like sewage so you can take that off your list of possible causes. There may be a sewer line break and the brackish water is getting back to your sump pit. Believe me, this is not uncommon, if the foundation isn’t back filled properly there can be air pockets in the fill. As the ground settles it can shear the sewer piping most commonly at the foundation. We are not trying to scare you, I’m just making you aware.

      4) I know this may be a little shocking but I think this may be the source of the problem. When a house is being built there are no toilets and quite often especially now with the lack of homes being built there is no satellite toilet either. I don’t think I need to get too graphic but the tradesmen building the house have no where to go so the ejector pit is the place. If the pit wasn’t thoroughly flushed out that could be the cause. Please don’t get freaked out it happens quite a bit.

      Hope I helped.



  24. Marcus says

    Thank you for responding:
    Here is the latest. A few weeks ago the builder sent out a couple of plumbers to do a peppermint test. We did not get a peppermint smell in the house however, after reading the post from your site, i questioned whether they had pour the mix in the right vent. Later in the week they returned and cut the pipe to where the sink and commode will go and the smell from the sink pipe almost knocked them off their feet. After cleaning the mud from the pipe and the pit he seal it shut. They then ran a camera through the pipe to see if there were cracks. The camera got stuck and they claimed that there were no visible cracks. The smell was gone and so was our problem smell (so we thought).

    Last week I hired a plumber to install an ejector pump. When he cut the vent pipe to the pit, all of peppermint water came splashing out of the pipe (hum). Once he was done he told me that the gasket to the vent pipe was missing and i could get one and place it on the pipe. Two days later the smell returned!

    Here are the answers to your questions:

    1. we dont have a floor drain in the basement.

    2. the condensate drain does discharge in the sump.

    3. the smell is definitely not coming from the sump.

  25. Matt says

    Hello, Have a rotten egg smell that has suddenly appeared in our basement bathroom.
    Had septic cleaned out about a month ago. No sump pump nor ejector pit. From what I understand eveything just drains downhill in our house. Have open floor drain in the basement that a sink and shower drain into it and that is the room with the smell. Smell is like rotten eggs. I think that it is at its worse if multiple loads of laundry are done. No other holes in the floor and the smell is only from the basement bathroom. Have a field and not sewer. Please let me know if you can help and/or if further information is needed.
    ps. this site is by far the best I have found so far

    • the plumbing info says

      Hey Matt thanks for the love, we appreciate it. On to your issue, my shoot from the hip answer to your problem would be that your basement floor drain isn’t trapped or that the trap is being compromised while you’re doing laundry. It’s possible that the water from the laundry is rushing past the trap and pulling the trap seal with it. The only thing that bothers me a bit is the nature of the odor. Rotten egg smell is hydrogen sulfide or sulfur, can you differentiate the smell from sewer gas? Let me know Matt, I’d be glad to help you further.


  26. Jeff Theis says

    We have recently noticed an odor in the lower level of our house. The level is finished living area and we have not had this problem in 18 years we have lived here. At first we thought it was possibly a dead mouse or even a gas leak (had the gas checked and found no problems) but can’t seem to isolate the smell and it comes and goes. We haven’t been able to tie it into specific activities like flushing or showering. We have a septic system. The smell does not seem to be coming from the laundry area or floor drain. Any ideas?


    • the plumbing info says

      You’ll definitely want to rule out a vent line break and that could be anywhere even though you are smelling it in the basement. Sewer gas smell is heavy and will settle in the lowest spot in the house. Do a peppermint test using the vent stack on top of the roof. If you smell peppermint anywhere in the house you have a vent line break somewhere.


  27. Gil says

    Hi. You have a very informative blog. I hope you can help.

    We have a city 3 flat with a basement apartment.

    No sump pit. Catch basin is outside. There are 3 washers and a slop sink in the basement that drain into a drain line tied to a floor drain line), and that flows into the main sewer line under the floor.

    About a month ago the floor drain backed up and we had the lines rodded out. Around that time, but I can’t say if it was before or after the clog, we started getting a heavy sewer gas odor in the basement. It wasn’t all the time, and we think it develops when the washers are used.

    The floor drains have P-traps (S-Traps?) which always seem to hold water in the bottom. I have tried pouring bleach into the drains. It doesn’t solve the problem, but at least I know they are not holding brackish water and they don’t give off any smell.

    The washers and slop sink are not on a vented line, but i don’t understand why they would push up gas only when used. On the days in between use, there is no smell.

    We just noticed that the water in the floor drain is tending to rise when the washers are used, with some evidence that the water is rising out of the drains a little bit as there are wet spots on the concrete.

    As I said, there is no sump pit, pump pit, nor anything like that. No smell coming from the 2 floor drains.

    The floor over the sewer line is solid wall-to-wall concrete, so even if there were a sewer crack, how could the gas get through the concrete? And do is so strongly?

    If the washer-sink-floor drain line were clogged with lint, could that push up gas, maybe back out the in-wall washer hose drain thingy?

    Any other thoughts?

    • says

      You have S-traps? I’ll give you my thoughts, you finally have your sewer flowing freely, it’s probably be slightly clogged for awhile slowing down the flow of waste water. Now that everything is clear the water moves with quite a bit more velocity. When the water rushes by the S-trap it pulls the trap seal with it. It’s a big reason why S-traps are illegal in many municipalities.


  28. Bob says

    Well after 6 months of looking we finally found the source of the basement oder. There was a crack in my toilet collar on the first floor of my house. The plumber replaced the collar and the basement oder is gone. Finally.

  29. Chad says

    We recently purchased our home and it appears the septic tank is running into the sump pit. There was never a sump pump in the house before and I had to install one. I even had the septic tank drained but it continues to backflow into the sump pit and every time we use the shower, toilet, laundry, etc. the sump pit just fills up and waste water is ejected outside. Any suggestions??

    • says

      Hey Chad thanks for asking the question. I have a few questions for you.

      Why are the sump pit and septic connected? How are they connected? They shouldn’t be and quite frankly it’s a health hazard especially because the pit isn’t gas tight. You’ve have to a have a tremendous odor issue? Please get back to me. The sump pit has to be divorced from the septic system. I’m afraid that your septic system is installed improperly.

      Is the brackish water leaching into the pit?

      Again let me know.


  30. Chad says

    Yes this really has me baffled. The brackish water is leaching into the pit and will flood the basement if the sump pump doesn’t work. There are also some solids that will appear at times. I assume they are connected because I tried to drain the hose from the pump into the cleanout in the yard and it would run continually. When I had the septic tank drained, I watched the pit as they were draining it and the water was all sucked out. It was fine for a couple of days and then filled up again. I have drained the pit all the way down and there is a 3 inch pipe on the bottom side of the pit and another drain in the bottom. I don’t think the drain is draining. There is a cleanout on the floor next to the pit and appears to be inline with the pipe. Is there some kind of valve that may be open or some kind of plug I can use to stop this?? The house was built in the 50’s and the basement was actually finished and carpeted at one time.

  31. Tania says

    I live in an 8 flat condo building. I am I’m the garden condo. The rehab of this building was done poorly 17 years ago. I have lived here for 6 1/2 years and recently over the past few years I have been getting some backup issue on a floor drain in my furnace room. To set the stage all the condos above me have their furnace and water heater overflow pipes converge into one big pipe that goes into this floor drain (in my condo). Recently, I have heard bubbling and now suds have been flowing up and the sewer smell is obvious. Why is this happening and how do i fix…or does the condo association need to get involved?

    • says

      @Tania first of all you probably need that sewer line rodded out. If you’ve never had issues before that would be the first thing you should do. If the line backs up through no fault of yours it’s most likely a condo association issue. We do this kind of problem solving all the time. A reliable plumber will be able to tell you and the association were the problem is occurring, inside your unit or at the waste connection for the entire building.


  32. ashlee says

    This was the only posting that helped. Thank you very much. You are the only one that mentioned the ac drain pipe in my basement. I poured water and bleach down the pipe and the smell went away instantly. Thank you because we were having people over for the weekend and I was so worried that my house was going to smell like POOP!!!!!

  33. Brad says

    I have an interesting issue that we just can’t seem to solve. I too have a rotten egg smell coming from my sump pit. I am on well/septic. We have lived in the house for 8 years and have never had an issue until now. Unusually mild winter this year.

    Smell will come and go (usually lasting a day). I don’t believe it’s sewage (as I’ve been around when my septic tank was pumped…I remember that smell…ug). pouring bleach in the pit helps a bit. Since it comes and goes I don’t think it’s a sewage line break.

    we have an ejector pump but it’s only pumping grey water from our water softener and laundry. it’s sealed and vented.

    no other water is entering the sump pit other than our from our weeping tile (as designed).

    We were told that the water table could have shifted and now we’re getting naturally occuring gasses in our ground water? But our well water doesn’t smell out of the tap (we do have it softened and also through an iron filter and whole house filter).

    I’m at my wits end as this stinks up the whole house for over a day and renders a full finished basement useless for a few days at a time. Is sealing/venting my sump pit a good option?

    Thanks much

    • says

      Hello Brad, Thanks for asking the questions. Let’s see if I can help you out. It is very possible you have a broken house sewer and the brackish water is seeping into the ground, making it’s way back to your drain tile system.

      It is very possible that the ground around your property has settled and some brackish septic water is getting back to your drain tile system. This would not effect your drinking water. I’d imagine your well is driven to a depth of at least 40ft to 60ft. and if that’s the case it would affect the water table.

      I’d suggest using dye tabs in your bathtubs and toilets. Keep running water and see if the dye makes its way back to your sump pit. If it does your sewer has a break.

      Hope that helps.


  34. John Tokatlidis says

    Where do I begin? I bought our house 2 1/2 years ago and I know that the basement has experienced some type of flooding in the past. As a result the previous owner put a pit in the basement floor that has a sump pump in it. There is a thick drain pipe that runs through the pit (horizontally) with a drain opening that comes up the middle (vertically). I previously had some smells coming from that open drain hole so I replaced the ‘back up protector’ with a new one that has a rubber stopper that holds the off the smell (and water back up). Everything seemed fine for about a year until recently. I noticed a bad smell coming from the pit and opened it up only to find several inches of murky water in it. The Sump Pump kicks in every so often and dumps the water out to the side of the house. The water is the result of a leak in the thick pipe that runs through the pit. A plumer friend suggested I use JB weld to fix the crack and vacuum the drain with my shop vac to clear it out.
    When I vaccumed the drain the water level was near the top of the drain hole opening and what looked like sewage waste was pulled out. I’m concerned that the pipe cracked because of too much water pressure – perhaps the result of a sewage back up. I don’t think that any of our toilets or sinks drain into this area – with one exception. The basement kitchen sink. A flexible drain pipe was retrofitted to drain near the top of this thick pipe.
    At the same time I have a tenant in the basement who believes the floor is rising behind the toilet. I’m not sure if this is actually happening or not, but I’m fearing that the concrete could be buckling. I’m thinking that the first thing I should do is call the city and see if there is a blockage to the sewer line. Any advice would be greatly appreciated….

  35. Larry says

    We purchased our house about 3 months ago. About 2 weeks ago, we started noticing a growing odor in the basement. Not an overpowering odor, but uncomfortable regardless. The strange thing is that the odor is coming from, what I would assume, is the least logical location. Furthest away from the sump area, water softner, any floor drains or plumbing pipes. The wall where the smell seems to be coming from is toward the front of the house and it’s a painted, block wall. No water leaks or visible moisture at all. We put a dehumidifier in there which made the odor disappear almost completely, but it returns when the dehumidifier isn’t running for a certain amount of time. We do have a septic field under our front yard which is my only guess as to the source. We haven’t experienced any of the common septic field issues that I’ve researched online (slow drains, flooding yard, etc). But with no visible moisture, it seems as if that isn’t the culprit either. Definitely perplexed as to whether it’s simply the way the basement smells come spring or if there’s a bigger problem that we’re missing. Any suggestions or insight would be greatly appreciated.

    • says

      This is an odd one to be sure. Here are my thoughts/questions to you. Do you have any vents that are in that area of the basement, do you have an ejector pit? Could there be a floor drain on that end of the basement that was carpeted or skim coated over? If not my first guess would be that you have some breach in your sewer somewhere. It maybe small and slowly drain into the soil toward the front of the house. It’s not a break large enough to create a leak but it’s enough to to leave things damp. When you put a dehumidifier in that location you’re removing the dampness from the area and hence the area doesn’t smell. I would say this is most certainly a septic issue. I Just consulted a septic system expert regarding your issue (Western Sewerage, Antioch IL) and he said there is a possibility the grading at the front of the house is slightly pitched back to the house and you may be getting some brackish moisture coming in at the seam between your floor slab and block wall. When the dehumidifier removes the moisture your problem is temporarily fixed. Hope this helps a bit. Let me know if you need anymore information.


  36. Larry says

    Thank you for the very quick response! Let me answer your questions.

    1) Not sure if an ejector pit is the same as the whole where a sump pump is. If so, that’s on the opposite side of the basement. Checked that…no smell at all.

    2) I don’t believe there is a floor drain on that side of the basement either. We just put down some carpet down there and didn’t see anything. The only two drains I’ve seen in the basement are about 15 feet away and the floor slopes in that direction. Regardless, I’m going to take another look.

    3) After I read your comments about the septic and the grade, I decided to take a walk outside and consider that possibility. Let me try and describe the house the best I can. The basement location where the odor appears to be coming from is almost directly below our front door. Looking out the front door, our garage is to the right and we have a porch that stretches about 10 to 12 feet ahead of the door and 20 feet to the left along the front of the house. Is it a safe assumption that any septic lines wouldn’t be below the porch and would most likely be a few feet clear of the porch? Our front yard slopes down towards the street at about a 5 to 10 degree max angle. The street is probably 30 to 40 yards away from the porch. I honestly have no clue where the septic pipes are and only suspect where the tank is. I suppose my follow-up question would be if it’s still possible that anything leaking from the septic field could still flow back towards the house considering what I just described. Thank you again!

    • says

      OK let me ask you this, has the septic tank been pumped out recently? If not that could be your issue right there. From what you’ve described to me it doesn’t seem like a grading issue but then again not knowing were the septic field is makes it difficult to diagnose with any certainty.


      • Larry says

        We were told by the sellers that the tank was pumped in October. We have an inspection scheduled for next week so I’m hoping to get a definitive answer. I certainly understand that it’s tough to accurately determine what the problem is with only a text discription. I’ll report back if I learn anything about it from the inspection. Thanks again!

  37. dorothy michigan says

    Hi, I have been smelling a oder of sewer in my unfinished part of the basement. I only have a floor drain. Put my nose to it and it seems that air is comming into the house from the floor drain with the smell. I had new plumbing put in throughout the house last year with pex. they replaced the toilet part of the drain to the sewer but they broke my stink pipe. They fixed it but it is behind the wall and it has been plastered over. But I can smell it comming from the floor drain. but what is weird is the air that is comming up. What are your suggestions? thanks so much dorothy

    • says

      My first guess would be that the p-trap is dried out. Take a bucket of water and some pinesol and pour it down the drain. That should do the trick.


  38. Greg says


    I own a small motel with 12 rooms. Room #7 in a building with 8 rooms has a sewer smell that I can not diagnose. It is a small room with a kitchenette. There is a kitchen area with stove, fridge and sink. The bathroom has tub/shower combo, sink and toilet. There is an in wall air conditioner in the kitchen and it is heated with electric baseboard heat. There is no nature gas on the property. The strangest part of this whole situation is that it is not consistent. The entire room will smell so bad you have to walk out and a few hours later there is just a hint of the problem. A couple hours later it will be horrible again. I can have the windows open and it will smell horrible or have them closed and it will be horrible. There seems to be no consistency. The first time it happened it was winter and the top of the exhaust had crusted over with snow. A few days after cleaning out the snow the smell went away. The next time was in April. It was spring like weather, no snow. This last time started about 10 days ago and the weather has been hot. I have had 2 plumbers over to look at it and they are stumped as to the cause. The following is a list of things that have been done to try to solve this problem:

    1. Checked all pea traps. Water in each one. Ran water through each one and flushed toilet several times.
    2. Cleaned all hair out of drains. Ran liquid plumber and bleach through all drains.
    3. Checked exhaust vents on roof for any type of blockage. Nothing. Dropped garden hose down them and ran water through vents. No back flow issues.
    4. Checked attic for smell. Nothing.
    5. Removed toilet and ran camera down the sewer line. No blockages. Lines clear. Resealed toilet with new gasket.
    6. Checked property for ground seepage. Nothing noticed.
    7. No wet spots on carpet area.
    8. Checked under tub. Area is dry.

    There is no gurgling in lines when you flush toilet or run water in problem unit or units next to it.

    Please any suggestions or solutions would be greatly appreciated. It is summer and we are losing $100 per day in revenue as I can not rent the room in this condition.. I have this room reserved in 10 days and have no where that I can move the customer. I will have to cancel his reservation. I do not want to let my customer down.

    Your thoughts please.

    Greg Loughins
    250 819 4198

  39. KAren says

    A new (built just about a year ago) but never used until recent basement shower, toilet, sink STINKS!!!

    Smells like sewer!

    i have washed thoroughly, used bleach in toilet, shower, and sink but the smell continues. Even from shower drain.

    When I use the shower, it seems the smell gets stronger!


    I hate the smell!!!

    • the plumbing info says

      Huh weird situation because the fixtures should be trapped so no smell should be coming directly from the fixture. Unless however your traps where being compromised somehow do to back pressure or trap siphonage. Do you know if your fixtures are vented in the basement? I’ve seen many basement bathrooms not vented that have the same issues. Let me know if that helps.


  40. sbryant says

    Hi, We have sewer smell in our basement for a month. We had a plumber out he used a camera he said we have sewer in our footer tile.We dug up the main sewer line by the house didnt find any leaks.We have a drain tile in the basement no sump pump or ejector pit but there is sewer coming out of it out side never did that before, the house is 17 years old we have a septic tank that tile in the basement runs under the main sewer line and septi tank. What would be the next step?

    • the plumbing info says

      OK lots of stuff going on here. First of all and it has to be asked. Have you had your septic tank pumped? If you haven’t that would be my first step. It’s very possible for the brackish waste from your septic field to leach into your drain tile and make its way to the house. How far did the plumber camera the sewer? If you did have your septic tank pumped then my next guess would be that you had a break in your house sewer somewhere. Its leeching into the ground water and making its way to the drain tile system. Hope this helps. Please leave another message if you have more information.


  41. Doug B says

    Great Website with GREAT Info… The problem I have is similar to others. I’ve been in house 11+ years never had any problems. Over the last week starting to get rotten egg smell from mechanical room in basement (sump pit NOT sewer, water heater, furnace). The only drain in basement floor is sump pit that drains into the back yard. Small bar sink drains into sump pit, but rarely used, typically only to drain dehumidifier tub (set on 40-50%)into it when drain hose gets clogged. No sewage (toilet) in basement, but can see black sewage line overhead. Have had homemade sump lid on or off for extended amounts of time over the years with no smell, until now. During the summer we were in a severe drought (Northern Indiana), could that have something to do with it? The smell is not sewer and not natural gas, just musty, rotten egg, yuck. It gets bad enough sometimes that you can smell it in room above (kitchen). Poured in some bleach last night helped for a while but wife called to tell me it’s back. Thought about throwing a toilet tab in?

    Any help would be greatly appreciated.

    • the plumbing info says

      Thanks Doug, rotten egg smell is sulfur. It is very possible you are getting the smell from the water. Are you on a well? Does your drinking water smell of sulfur? Let me know, we’ll get to the bottom of this.


  42. Rob says

    Sewer Smell coming for Sump Pump

    I have read a lot of sites and this one seems to have to best solutions
    I have been getting a bad sewer smell from my sump pump pit when i use my washer
    my washer drains into a wash tub then drains into the ejector pump , my sump pump is on the other side of the basement, i noticed water entering the sump pump pit through the corrugated when the washer drains, that is when i get the heavy smell, the water trickles in , any solution Thank You

    • the plumbing info says

      Thanks for the kind words. So your ejector does not cycle when the washer is on? It only goes to the sump pit? If that’s the case then there is the answer. If your ejector comes on and you are still getting some of the water into your sump pit then you have another problem. I would say you have crack in your sewer line somewhere and it’s making it’s way back to your sump pit. There is an easy way to see if that is occurring. Have a plumber die test using your laundry tub. Fill the laundry tub full of water and have them use plumbing dye (food coloring can work but it breaks down and it’s not very bright.) If you see the dye come back into your sump pit there is your issue.


  43. Todd Phelps says

    We have an ejector pit installed in our basement with all new lines and fixtures in 2010. In the room next to our ejector pit (seperated by walls, etc) – we have a very strong sewer smell…comes and goes, etc. but has been very strong over the past week. I can alleviate by leaving the window open and the smell is gone, but returns…no smells anywhere else in the house or by the pit. IT seems to be most prevelant in the winter. My thoughts are the vent goes to the roof and comes out on the North side of house. Here in Colorado, north facing in winter is bad since it get’s no sun…could it be bound with ice? What a great site!!

    Todd Phelps

    • the plumbing info says

      Hey Todd thanks so much for the kind words. Believe me the site is only going to get better. On to your problem. Some of these questions are just to rule things out. Is there a floor drain in the room with the odor? Did someone cover it when putting in flooring etc.? How is the vent line piped coming out of the pit? Does it go straight up and tie in to the main vent stack? Does it run into the wall separating the two rooms? Answering those will help big time.


  44. Mel Bazz says

    We have an unidentified odor that only comes out when we use or walk around the basement. The smell is not constant. It smells like fish. We had a condensation line run to a floor drain and then cemented over it about 2 years ago that I suspect may be the issue? The plumber who ran it says it is not possible. We have had a plumber, electrician, hvac and builder try to figure it out. We have even had an air quality test done because they said it would identify all of the smells. It didn’t identify the mystery odor. Because of the smell we cannot use the basement.

    • the plumbing info says

      Please help me a bit here. You say the odor only comes out when you “use or walk around the basement”. Does that mean that the act of walking or using has a causal effect on the appearance of the odor? Again I’m not trying to be a smart guy I’m trying to wrap my brain around your issue. Having a fishy smell in drinking water although not common can certainly happen. It usually happens in cities that get their fresh water supply from a river. During the river run off season sometimes bacteria gets in the water and the water treatment plants can’t remove all of the unpleasant smell. I suspect this isn’t the case in your situation. I do however believe it is a bacteria issue. The first thing I would do is uncover the floor drain your plumber covered over. I have no logical explanation as to why this was done. Condensate should always be drained into an open-site drain. Covering it will only promote stagnant water and bacteria growth. If you have any other information I’d be glad to take a look at it.


  45. Lela says

    Thank you for the information! We just had a Sewage Ejector Pump installed in our condo so we can have a way to do laundry in home and within 8 hours of using it for the first time the smell started. The plumber gave a lot of suggestions that have failed, I’ll be calling to have him come run the Studor vent through the roof since it’s currently venting in our laundry/utility room instead of completely outside.

    • the plumbing info says

      Studor vents are illegal in most municipalities around the US. The problem is it’s mechanical and if it fails you’ll always have an issue. They have their uses especially when venting an island kitchen sink but I don’t recommend them especially in your situation.

  46. John says

    Great site and great answers. We have an ejector pit problem. Shower, toilet and sink drains to ejector. We stopped using the toilet. We still get intermittent smells. It varies. Sometimes when you run the shower. Sometimes just depending. The Main vent stack had a hole I sealed it. helped a little. However, when pit ejects, on occasion, water will back up into drain line for the washing machine. The washing machine does not drain to the pit but, it is tied to the main. My guess is ejector pit is too strong…pushes water gas through the system…? the ejector pit has 2″ pipe, and 3″ vent. Maybe pipe is too small causing too much pressure. Not sure. SOS

    • the plumbing info says

      Thanks John for the kind words. Is the washing machine in the basement with the ejector pit? If you have a gravity sewer that runs underneath the basement floor why do you have an ejector? Without seeing the piping configuration on the outlet of the ejector it’s hard for me to tell why you would get some backup in your washing machine line. Pop a couple pictures for me and send them to and I’m sure I can figure it out for you.

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