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Author:
gbecki49 (MO)
We've been battling a sewer gas smell in our home for years. I've had enough, but have run out of things I know to do to try to find and stop the problem. Some history: We only have the smell during the warmer, more humid months, and not every day. The smell seems to originate in the laundry room. There was an "s" on the laundry plumbing rather than a p-trap so I changed that out. We were smell free for about 3 weeks, but that isn't unusual. It doesn't seem to matter whether the windows are open or closed, but if the smell starts, it will generally go away if I turn on the air conditioner. We don't have central heat or air. Window units and baseboard heat. If I turn on the attic fan, I am guaranteed to have a really bad blast of sewer gas smell throughout the whole house. We've put water down the stack to make sure it goes all the way down and it does. We've smoke tested the stack and we get smoke out the top. None of our traps are dry (unless something is causing a siphoning effect) as they are all used daily. Is there anything any of you can think of that would be causing this short of a bad vent stack? Is it time to peppermint test the stack? I want to try everything I am capable of before I have to call a plumber. Nothing against you guys...I'm just broke! Thanks in advance for any help/thoughts you might supply. Oh, we're next to last at the end of the city sewer line on our side of the street. Could that have anything to do with this?
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Author:
eric_anderson (CT)
I think the key is that it goes away with the AC on. My guess is the AC condensate line goes into the waste line soemwhere via its own trap.
When it dries out, you get the sewer gas. When you run the ac, the condensate primes the trap and the smell goes away.
P.S. I am not a plumber but the there are a couple of traps in my parents house that have to be primed manualy every year or so.
Cheers,
Eric
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Author:
TFR (CA)
Trap syphoning (poor venting), bad seal at wax ring on a toilet, sewer back flow from city, break in a drain line. A dirty tub or shower drain.
I read your post again and your position on the city sewer line is something to investigate. Your city or you may need to install a check valve on your main line.
Edited 2 times.
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Author:
gbecki49 (MO)
Thanks for the reply Eric but we don't have central air. We have window units so there isn't a condensate line. Good point though!
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Author:
gbecki49 (MO)
TFR, thanks for the reply. Stupid girl question here: how do I know if this is a case of poor venting that is causing siphoning? Toilet gaskets are new and properly installed, drains are cleaned about every 3 months. That leaves poor venting, or a problem with backflow or our positioning on the city line, right? So, IMHO, poor venting is what I need to check out first. If it isn't that, then the city needs to do some checking on THEIR dime.
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Author:
dlh (TX)
it isnt poor venting. as long as you have a vent at all the smell will go out the vent but if you have a restricted drain it could siphon a trap, the trap doesnt have to be completely dry for sewer gas to escape through it.
you said you did a smoke test but you said you only seen the smoke come out the top. when doing a smoke test, all outlets (vents and drains) should be plugged while a little pressure is added along with the smoke. otherwise it wont really tell you anything.
the peppermint test might be worth trying
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Author:
waukeshaplumbing (WI)
could be a dead mouse in the wall...that would explain how it comes and goes...we get that smell 1 or 2 x a year....lasts 2 weeks
could be a nail which cracked a vent pipe in the wall....
i dont know why the smell wouldnt be constant.
do you have a roof vent near the laundry?..windy days could push the smell down.....
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Author:
Shoemaker2 (MA)
Are you sure that the hose for the washer is not reaching into the stand pipe too far, and siphoning the seal after the washer discharges? I have found that to be the cause many times. Also I would check to see if any line may have been hit with a nail or screw while putting in shelving or any other accessories.
Also look for unused floor drains, or fixtures.
I once was call to a home to find a sewer smell and it turned out to be a rotten boneless turkey breast laying on the bedroom floor under a kitchen towel, Seems the daughter thought it made a good ice pack for a sore muscle (a month prior) but didn't bother putting it away. What a stink!!!!!
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Author:
x apprentice 22 (MA)
Did you add a vent to that laundry p trap? p traps will still siphon with out a vent.
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Author:
dlh (TX)
they may siphon without a vent but there is usually a restriction in the line that causes that even
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PLUMBERS "Protecting The Health Of The Nation"
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Author:
gbecki49 (MO)
I'm sure this isn't a case of a dead mouse in the wall. When the smell does come, it never lasts for more than a few hours at it's worst. The vent stack DOES run right up through the laundry room wall just behind and to the left of the washer. The smell seems to be more apt to show up when the wind is out of the east. Any way to stop this if it IS the wind blowing it back?
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Author:
gbecki49 (MO)
I'm pretty sure the washer hose isn't too far into the stand pipe, but I'll try to adjust it and see what happens anyway. The only place in the entire house (a tri-level) that we could have punctured the pipe with a nail would be in the kitchen. It's the only room the stack runs through that has a wall that anything would have been hung on. When my husband purchased the house in 1990, the plumbing for a full bath was stubbed in down in the basement. He had the bath installed at that time. There is a closet just behind the bathroom. I noticed the other day when I was in there trying yet again to figure out the smell that the floor sloped a bit at one point. I wrecked out some of the dry wall at the base of the wall and looked into the wall and noticed what appears to be an unused floor drain. It is directly under the bath tub. It appears to be capped. We have never noticed the smell in that bathroom, or in the one upstairs for that matter. It is always in the laundry room and in the aforementioned closet where all the plumbing terminates. Anything I need to do with this drain to make sure it isn't the culprit?
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Author:
gbecki49 (MO)
There was already a vent there.
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Author:
TFR (CA)
Good puzzle you have here! Reading your on going posts and replys, I'm a little less suspicious of city back up and more suspicious of traps and possible broken lines or nail holes as was suggested.
The best thing you have going is the fact that you sound very industrious! Doing you own trouble shooting is saving you money. These calls are tough, the symptom must be present in most cases for a diagnosis.
With that said, I love a good puzzle. So... what year was the home built? Is the laundry room the obvious origination of the odor? Where is the laundry room located in the home? Has the home been modified extensively? The floor drain discovery, where is that located in relation to laundry?
If you are clean and comfortable... thank your Plumber.
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Author:
gbecki49 (MO)
I love a good puzzle too, but this one is about to drive me nuts!! We'd eventually like to sell this house and I'm seriously doubting we'll have any takers if they come to see the house and walk in and get hit in the face with this smell!! I appreciate you being so willing to try to help solve this mystery. Answers to your questions below:
So... what year was the home built? 1980
Is the laundry room the obvious origination of the odor? Seems to be.
Where is the laundry room located in the home? North side of the house on the ground floor. This is a tri-level home. Bathroom above the laundry room and a closet (that sits behind the other bathroom) just below and west of it in the basement and where the plumbing for the entire house terminates. Vent stack runs from this basement closet, up through the laundry room, then up through the kitchen wall, then up through the upstairs bathroom wall and on out.
Has the home been modified extensively? Not at all. We are in the process of a complete re-do, but it is all cosmetic. Nothing structural. My husband purchased the home in 1990 and nothing had been done to it at that time. Plumbing for the basement bath was stubbed in, but no fixtures set or walls up. He hired someone to build the bathroom and set the fixtures.
The floor drain discovery, where is that located in relation to laundry? This is in the basement bathroom, under the tub. Bathroom shares a wall with the basement closet.
Thanks again for your help!
Becki
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Author:
TFR (CA)
If the odor's source point can be traced to laundry room and that's where the vent for the main sewer travels up through the walls. If it was me and the odor was strong, I would access the stack (open the wall) to inspect for cracks or holes. There are devices you can buy that 'sniff' for gas. UEI is a manufacturer of some good ones, go online under 'sewer gas detectors'. Short of opening the walls at this point, given the info you have gathered you will be spinning your wheels. You will find the source, because the smell should not be there and HAS to come from a compromise in the sewer system.
If you are clean and comfortable... thank your Plumber.
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Author:
gbecki49 (MO)
Thanks! Before I open the wall, I think I may try renting a sewer camera and snaking it down the stack to look for cracks or nail/screw holes, etc. Since the stack runs up through 3 stories, I'm trying everything I (and kind folks like you) can think of before resorting to wrecking out the walls. Thanks again, and have a great day!
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Author:
michaelkersch (NY)
WIND WIND WIND!!
I have an intermittent smell problem and I'm correlating it to very windy days. The roof vent is 8 ft from a neighboring building facade and wind swirls up there and it must create a positive or negative pressure in the pipe which empties the trap on my ground floor apartment unit.
Just a thought, M
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