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Basement Sewer Smell

1704 Views 6 Replies 6 Participants Last post by  gregzoll
It appears that my basement sewer doesn't keep enough water in it. I have lived in this house for 4 years. Shortly after moving in we noticed a smell and looking down the sewer pipe did not see water.
We added water and it stopped the smell.
We noticed last night when we turned the attic fan on that the sewer smell was in the basement but went away shortly after turning the attic fan off.
We did not have this problem in the past using the attic fan.

Is there a reason why a sewer would not hold a certain level of water?
Would adding some water periodically be ok to do?
Is there any other chemical that I should also add to the sewer to help with smell?
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Can we assume you are adding water to your basement floor drain? It is normal for the to dry up over time. After adding the water, add a 1/2 cup of vegetable oil. It will stay above the water and prevent the water from evaporating.

I agree with RJNiles that the smell is most probably coming out of your basement floor drain.

Where I live, every house has something called "weeping tiles" near the bottom and around the exterior of the house's basement walls. The purpose of those weeping tiles is to allow excess ground water to drain away so that you don't have water pressure on the outside of the basement walls causing water to want to penetrate into those basement walls.

Those weeping tiles will either drain into a sump pit in the basement of the house, or into something called a "catch basin" which is little more than a big drain pipe that connects to the main sewer drain pipe from your house.

If you have a sump pit in your basement, then the sump pump in that sump pit will either pump the water in the sump out onto your property somewhere, into the sewer drain pipe or into a separate pipe that connects to a separate storm sewer under the middle of the street your house is on, depending entirely on what your local plumbing code calls for.

If you have a catch basin in your basement; often called a "basement floor drain", then the basement washer will often be set up to drain into that floor drain so that you refill the trap at the bottom of that catch basin every time you do laundry. That way, you prevent a sewer smell from coming into your house even when a long drought would otherwise cause that floor drain to dry out.

So, yes; if the smell is coming out the floor drain (and it probably is), adding water to the drain periodically will prevent that smell. That's because there will be a large p-trap at the bottom of that floor drain, and the pipe downstream of that large p-trap connects to the main drain line from your house.

I'm just a little uncomfortable with pouring cooking oil over the surface of the water in the basement floor drain, although I fully understand the reasoning to do that. Mold and mildew can use vegetable oils and animal fats as a food supply. Once mildew or mold starts to grow in that floor drain, it might be hard to get rid of it because that area is often wet because of rains and snow melt. I'd say the better option would be to pour a small pail of water into that floor drain every few months to keep it full. It's the water in the large p-trap at the bottom of that floor drain that forms a physical barrier between your basement and the rotting putrifaction in the drain piping underneath your basement concrete floor, so you need to keep that large p-trap full of water if your washing machine isn't keeping it full when you do laundry.
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I have always used vegetable oil but it is of concern you could use mineral oil. Baby oil is a perfumed mineral oil.
If you are using an attic fan, meaning a whole-house exhaust fan, you should be opening windows or screen doors to allow air in. If you don't, the fan will suck air into you home from wherever it can, and sometimes those places don't smell good.
get us a picture of the drain you are talking without the cover and one of the cover..both side....there is a method to my madness..:smile:
If it smells like a wet organic smell, it can be a leak in the waste piping, or if the cover is not on the sump if you have one, which are now supposed to be sealed tops, that can cause you to smell anything that can be leaching into the ground from waste lines, especially if you have a Septic system and have had a lot of rain recently.
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