Sewer Smell in Half of the House

I am getting a sewer smell in 1/2 of the house. I will give some of the pertinent info to help in formulating a suggestion.

We are on a septic system. It was just pumped 9 months ago. We have 2 full baths on the main floor with a tub/shower combo vanity in one, whirlpool tub, shower and vanity in the master. These two share a wet wall and have a 2" vent pipe that goes to the ridge of the west facing roof. There is no smell in this area of the house.

We also have a laundry room with w/d and utility sink, double sink in Kitchen w/garbage disposal, and d/w. They share a 2" vent pipe on the west side of the house. This is the area, mainly near the w/d, and utility sink, that the smell is most prevalent. The smell is really only prevalent on windy, wet and rainy days. The prevailing winds are out of the west. The septic system and leach field are also on the west side of the house. There is also a very gentle slope toward the house from west to east. This means the leach field is about 12-18" higher than the top of the basement foundation.

The house is only 5 years old and we are the original owners. I have my doubts about the size of the vent pipes. I feel that there should have been at least one 3" vent, but I am not a plumber. We had the same problem in other areas of the house but I put a PVC mushroom cap on the vent above the area and it remedied the problem. I tried this on the second 2" pipe, but it made the problem worse.

Please feel free to ask any questions that may help in your diagnosis. I am at my wits end and my wife wants to move.

Thanks in advance for all of your wisdom and advice!

Steve

If you have three pipes going through the roof, that would add up to the 3" cross section for venting.

Are you sure the washer has a trap on it?
I'm sure it does, but it is something to check.
Is there a floor drain in the laundry area, sometimes under the washer?
If so, make sure there is water in the trap.

Just to clarify, There are only (2) 2" DWV pipes coming through the roof. They are about 35 feet apart.

As for the floor drain, we are on a basement, so ther is not a drain in the floor.

The vent pipes protrude roughy 18-24" above the pitch.

Thank you for such a quick reply!

I believe the problem may be that there is not enough venting.
I have 4 sinks, 3 toilets, 2 bathtub, whirlpool tub, shower, d/w, w/d, and utility sink. I have (2) 2" vents and (0) mechanical vents. Shouldn't there be at least (1) 3" vent? I am in Indiana and can not decipher the code.

My other guess is that the smell may have to do with the sump system. The smell is only prevalent when the ground is wet. Our leach field for the septic is uphill from the back of the house. The closest area is about 60' from the back of the house and is about 12" higher than the top of the foundation.

Thanks in advance for all of your help.

Is your sump connected to your sewer system? If it is you should remove it and run it out your sill and away from your house.

My sump is drained out the side of the house into the ground and releases about 75' to the front "down-hill" from the house.

You should have a floor drain in your basement somewhere if that is where the laundry and hotwater tank is, that is code. Terry is correct, check for empty traps or no trap on something. If you are correct then you could be siphoning a trap without proper venting. Slowly dump water into all the drains and see if the smell stops, especially high output volume fixtures like the washer and dishwasher. Your back wall toward the septic system is not wet is it? Is the sump pump pit open or sealed?

Also a dead rodent can smell like sewer sometimes. I hunted for a sewer smell before to find a dead mouse.

Where do the lines to the septic system run in relation to the sump?

How old is the septic system?

Cass said:

How old is the septic system?

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coltsfan said:

The house is only 5 years old and we are the original owners.

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My guess is the field is too close to the house, OR if he has a sewage ejector, it has a leak in the venting.
He mentioned his field is 18" above the slab.

GrumpyPlumber said:

My guess is the field is too close to the house, OR if he has a sewage ejector, it has a leak in the venting.
He mentioned his field is 18" above the slab.

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Actually, he said "foundation"..this would mean he likely does have an ejector.
The gromets on those are often suspect...just my hunch.

He said it was pumped 9 months ago and i was wondering if it was in failure and burping getting ready to back up and allowing some gas in.

Thus the age of the field question.

Cass said:

He said it was pumped 9 months ago and i was wondering if it was in failure and burping getting ready to back up and allowing some gas in.

Thus the age of the field question.

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I know...thats why I pasted the 5 year thing.
I'm just real impressed with myself for catching a detail, usually it's you telling me I missed something.
BTW, Merry Christmas buddy.

Oups I missed the 5 year old thing...but I just worked on one that was 7 years old with a busted pipe that gave the impression that it was in failure. crushed and busted by a truck, Im not sure why it worked for 7 years.

Thats why I asked about the main lines relationship to the sump pit. It sounded like poo water in the pit...
Maybe a separation/misalignment just outside the foundation.

Wow! Thanks for all of the replies. I will try to answer them the best I can.

The lateral lines move from NE to SW away from the house. I am on a 9 ft basement foundation with no second story. The lateral lines start about 40ft from the back of the house and move diagonally to about 70 feet from the house. The sump pit is in the N corner of the Basement and it is covered, but not airtight. The exit pipe to the septic system is about 6' feet above the basement floor.

We do not have a drain in the laundry room, however both of our hotwater heaters are in the basement and there is a drain there.


I am in the process of adding water to all drains and we will see if that works.

There are absolutely no moisture problems in the foundation walls. Have had a sump pump failure about 2 yrs ago that put 18" of water. Now I have battery backup and water backup.

Thanks again for taking time out of the holiday season to help a complete stranger with a problem. Merry Christmas to everyone!

coltsfan said:

Thanks again for taking time out of the holiday season to help a complete stranger with a problem. Merry Christmas to everyone!

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No problem, as long as you can forgive Brady for breaking Mannings record next week.

coltsfan said:

The sump pit is in the N corner of the Basement and it is covered, but not airtight. The exit pipe to the septic system is about 6' feet above the basement floor.

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How close are they? Is the sump directly below, 6' from the main?

Are there foundation drains going to this sump?

Redwood said:

How close are they? Is the sump directly below, 6' from the main?

Are there foundation drains going to this sump?

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The sump pit is about 20 ft away from the pipe going out to the septic.

there are foundation drains into the sump.