Sewer Smell From Sump Pit

Jesse Robinson · 09-23-2012, 06:17 PM

The sump pit that is in my house is connected directly to the sewer line. The water from the clothes washer goes into the pit. There is a black film along the base of the pit that apparently has been there for a long time (just bought house). The pit smells like rotten eggs and makes the house smell. There is a check valve (plumber changed out twice now) and he also put in a P trap and some other trap to keep anything from coming back into the pit from the sewer. The plumber also dry-vac'd the pit which he said smelled terrible. Since then the smell has come back. Why does this pit still smell? What is the black film? Blackwater from the sewer line coming back in somehow? The water in the pit is definitely black at all times. I'm thinking about moving the whole setup to the other end of the basement and connecting the washer directly to the sewer injector. Any other ideas before I move everything?

Thanks.

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**Scott Patterson** · 09-23-2012, 06:57 PM

Originally Posted by Jesse Robinson

The sump pit that is in my house is connected directly to the sewer line. The water from the clothes washer goes into the pit. There is a black film along the base of the pit that apparently has been there for a long time (just bought house). The pit smells like rotten eggs and makes the house smell. There is a check valve (plumber changed out twice now) and he also put in a P trap and some other trap to keep anything from coming back into the pit from the sewer. The plumber also dry-vac'd the pit which he said smelled terrible. Since then the smell has come back. Why does this pit still smell? What is the black film? Blackwater from the sewer line coming back in somehow? The water in the pit is definitely black at all times. I'm thinking about moving the whole setup to the other end of the basement and connecting the washer directly to the sewer injector. Any other ideas before I move everything?

Thanks.

If it is just a sump pit/crock with a pump it will most likely not be vented or will it have a lid that has a gasket and is bolted down; this is why it stinks. It also sounds like you have sewage backing up into it. If it is lower that the main sewer line traps are not going to do anything.

Take some pictures of the sump, valves, etc... Photos are a ig help.

Jesse Robinson · 09-24-2012, 06:23 AM

It is definitely lower than the main sewer line. I think it may be vented but not tightly sealed lid on it so the vent couldn't work anyways.

Jesse

**B vanderhoof** · 09-24-2012, 07:10 AM

Once I had a similar problem and found out that the cast iron drain from the kitchen had rusted through at the point where it passed through the block wall - and the waste had been leaking down inside the wall and entering the drain tile/sump pit. The organics in the water caused the pit to stink as you describe and was very dark in color. I had excavated on the exterior and saw no problem with the drain until I broke the block open to reveal the cause of the problem.

**Jim Robinson** · 09-24-2012, 02:08 PM

Those photos are hard to work with. Is there no lid at all? That larger line on the left looks like it's a toilet draining down into the sump, or is it a vent? Vents are not usually that large on a sump pit. I would think your plumber would have noticed that, however.

Exactly what drains into the sump? Is it supposed to be only the washing machine, or do you know that the toilet is also draining into there?

Jesse Robinson · 09-24-2012, 02:37 PM

There is no secure lid on it at this point.

I will get some better photos up there. The large white pvc line is the sewer line running back to the front of the house which thankfully doesn't run into the pit.

What runs into the pit that I know of: 1)there is a larger galvanized pipe which looks to just be connected to the floor drain, 2) a drain from a bar sink which is no longer being used, and 3) the washing machine.

I think the floor drain would receive water if there was a flood in the basement. When I looked into that drain is is highly corroded but did have a black color in the very bottom of it, but didn't seem to be carrying the rotten eggs.

I am almost positive that there is no toilets running into the pit. The vent is on the line that is running in from the washing machine. There is a pipe that runs straight up the wall from there. The plumber smoke bombed everything and said there are no leaks in any venting as well.

**Scott Patterson** · 09-24-2012, 02:58 PM

An easy way to tell what is flowing into it is to get some food color and pour some into each toilet(use a different color for each toilet) in the house and give them a flush (Wait a few minutes between each). If you see colored water flowing into the sump ya know that you have a toilet connected to it! The color that flows equals the toilet that is connected to the sump!

**Nick Ostrowski** · 09-24-2012, 04:38 PM

Have you noticed any toilet tissue inside the pit?

Tom Thompson · 09-24-2012, 07:48 PM

Originally Posted by Jesse Robinson

It is definitely lower than the main sewer line. I think it may be vented but not tightly sealed lid on it so the vent couldn't work anyways.

Jesse

If you don't put an air tight vented lid on this, enjoy the smell.

**John Kogel** · 09-24-2012, 09:39 PM

Right, if it empties into a sewer system, as laundry water should, it is sewage and needs a tight-fitting lid and a tall vent pipe that vents the stink out thru the roof.

An open basement sump pit is meant to be for ground water only and would empty into a storm drain, no stink. Too bad the plumber didn't explain that very well.

It may have been a groundwater sump pit originally and had the laundry drain added. All that greasy soap and dirt makes a nasty smell in a short time.

**Eric Barker** · 09-25-2012, 06:04 AM

I agree with John. In my experience laundry water can be a notable source of odor and in the older homes the waste water sumps were not sealed and vented. I always recommend upgrading to current practices.

**Steven Saville** · 09-25-2012, 06:07 PM

Originally Posted by Scott Patterson

An easy way to tell what is flowing into it is to get some food color and pour some into each toilet(use a different color for each toilet) in the house and give them a flush (Wait a few minutes between each). If you see colored water flowing into the sump ya know that you have a toilet connected to it! The color that flows equals the toilet that is connected to the sump!

Sometimes hard to tell color. Had a job once which suspected restroom was discharging into stormwater system. Confirmed by flushing miniature marshmallows and seeing them them float by in nearby stream.

Floor drain was mentioned in OP with galvanized line above. This could be the waste from kitchen sink. Many homes have this setup in which kitchen sink ties into 2" soil pipe below basement floor along with the basement floor drain.

In any case should NOT discharge into sump pit. If it does, kitchen grease, food waste, etc would definitely leave the black scum mentioned as well as horrible odors. Furthermore, drainage from washer would also leave soap scum and odors. As mentioned by others sump pit should only discharge stormwater.

**Dan Hagman** · 09-27-2012, 07:46 PM

Are you on a septic system? Once I had a sewer smell in my sump pump pit and cleaned it out and it kept coming back. Just outside my house I dug down to the sewer pipe going to the septic tank and found a broken PVC line and every time we flushed some of the the toilet water washed out the broken pipe and down to the tile around the house and found its way to the sump pump pit. I repaired the broken sewer line, flushed out the pit a few times and the smell was gone. Just another thought.