septic odour issue

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Sheri

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Jun 24, 2011
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Location
Ottawa, Ontario
I'm having a problem with my septic tank that has the Twilight Zone music drifting through my head. It just doesn't make sense.

I've noticed an odour when I do laundry - specifically the methane septic odour. It comes from the general area where all the pipes join to exit to the tank.

There are no leaks, and the tank has been pumped.

The odour occurs ONLY when I do laundry (this is where it gets weird). I've gone downstairs while the shower was running and after the dishwasher has run and there's no smell!

Has anyone heard of this? If there's a problem shouldn't I be getting smells all the time?

Help! :confused:
 
I don't think that I have any definitive answers for you, but I will ask a couple of questions that might help in tracing the problem.

This area where all of the pipes come together. How do you know that the pipes join together in this area? Is the piping exposed? Is this area close to the clothes washing machine? Is there a pipe with a strange cap on it in this area?
 
To add to phish's questions; Is this a new issue or always been there? How old is the septic system? (original with the house, over 30 yrs old?) When you do laundry, is there a way that you can confirm that the water goes to the tank with the other drains?
 
the pipes are exposed, and yes fairly close to the washer. I'm able to see and follow all the pipes from sinks, toilets, etc to the outlet. No capped pipes, and the washer has its own pump for pushing water into the septic.

this is a new issue, the tank was pumped last month. the company that does it have been around for generations - same one that inspected when we bought and its fine. it started, if I remember correctly, just before we had it pumped and we were hoping that would fix the problem.

the house was built in 2003 - so everything is relatively new.
 
Oh yes. We love picture.
Especially of Cars, Jeeps, Boats, guns, knives and fishing.;)
Pictures are always helpful.
 
I could do cars, boats, guns and fishing... no jeeps, nor notable knives. BUT since it IS a plumbing question, I'll post some pics. Stay tuned. :p
 
here's two pics - one of where the washer sits and one of the outlet area... does this help? They go end to end with a couple feet of pipe in between...

Picture1.jpg

Picture2.jpg
 
There is a possibility that the wax ring seal underneath a toilet is letting some sewer gas through. Is there a toilet on the first floor above the piping in the photo? A higher volume of water, such as from doing laundry, has been known to push sewer gases through even the smallest of openings in a wax ring.
 
I'll look into that, thanks. I've also determined that the smell occurs only during the first load of wash... does that fit with the wax ring theory?
 
Yes, it could fit with the theory, but remember that these things are hard to diagnose over the internet. If your pump is holding some water, which they usually do, and it gets stinky, which it usually does...the first load might blow the stinky water through. You still should not get an odor if the pipes and all connections are sealed. Even a small space between the lid of the pit will allow sewer gas through.
You may have to do some serious investigating to find out where you have an opening for the gas to get through.
 
If you could provide a better description of the smell, that may help. Methane does not actually have an odor. The septic would give off a sulfur odor that is the telltale sign of anaerobic digestion. If the pump is holding water, but there is no organic matter in there, it would cause more of a musty odor.

As Caduceus pointed out, gas should not be entering your house if the pipes are sealed. Any air in the line should go out the vent. The way to test this is to put smoke in the line and see if it comes out in the house.

Since you are in the basement, do you have a floor drain? In our business, 90% of odor issues where there is no obvious culprit are dried out floor drains. This could explain the situation if the floor drain is not used and gets dried out, water from the washer could force air out of the floor drain and and then form a seal itself, therefore there would be no odor during subsequent loads. Without seeing the property, this is just a guess.
 
I say methane because we have a sulfur filter that vents and gives that hydrogen sulfide smell. This is different - its a sewer smell. Its also right around all the pipes in the pics I posted. We dont have a drain, just a pit with a sump.

I think I can see where the first load of wash would blow the gas through, but I need to figure out where its sitting beforehand. We've cleaned the filter on the pump and never noticed a smell when we open it up.

When you say "lid of the pit" are you referring to the lids on the tank outside? Its concrete on concrete so its not a great seal - we noticed that when we had it pumped. We cleaned away the grass and dirt around the lids but now I'm wondering if that was maybe a bad idea.
 
When I mentioned the lid of the pit, I was referring to the lid of the pit that is next to the washing machine/dryer and lifts the water to gravity drainage.
 
The septic tank should be vented anyway, so cleaning around the lid shouldn't cause this problem.

When you cleaned the pump, was it after a load of laundry? This could be why there was no smell.

Where did you find that gas could be coming through? Could you send another picture?
 
Ok - its not a pit next to the washer, its a pump. There's a small cover than can be taken off for cleaning a lint trap.

I can send a pic of the pump/pit for the washer later today.

Pekasus - that's the problem - I can't figure out where the gas is coming through...
 

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