Sewer smell

[RickL]

I have researched sewer smells but can’t find one that really matches what we are experiencing so I’m reaching out to the group to see if anyone has experienced something similar. The other day after taking a shower I noticed a sewer stink. Then after the wife took hers it really was obvious. Being an Oshkosh we have a washer in our slide and when I opened the doors it was enough to almost knock you over.

Earlier this summer I stayed at a campground that didn’t have sewer hookups as the campground was in a flood zone (was along side the Mississippi River in Wisconsin) so they run a honey wagon around. I had used this service one other time and noticed a short while later I had the same sewer smell so I changed out the air admittance valve (studor). So I ran and picked up another valve (actually 2) and replaced the valve.

After airing everything out we had no issues with the smell. Unfortunately after taking another shower today the smell came back and after checking the closet where the washer resides it was strong, although not as strong as the previous day.

So my question is, is there another air admittance valve in the slide hooked up to the drain for the washer? That’s the only other thing I can think could be the issue. I’m hoping not as there is no access other then cutting into the wall an where would one start to cut if there is? Which if there would be one begs the question whose the brain surgeon that would design something that wouldn’t install an access panel.

 

[danemayer]

Sometimes the space under the sinks is limited and instead of a p-trap, a HEPVO valve is used. It can also get stuck open allowing free flow of holding tank odors.

 

[cookie]

This past summer we had a very similar situation. Wife was in the shower and I detected a sewer odor and like you it seemed the most intense at the washer closet.
After about 2 seconds of thinking I decided the odor was coming from the washer drain stand. The water in that p-trap must have splashed out while traveling.
I poured a half cup of water in the drain, problem solved.
So try a little water in the washer drain.

Peace
Dave

 

[RickL]

Sometimes the space under the sinks is limited and instead of a p-trap, a HEPVO valve is used. It can also get stuck open allowing free flow of holding tank odors.

Dan, thank you. I think you hit the nail on the head. I checked and my kitchen sink has a Hepvo valve so I’m going to assume the washer drain also has one. I’ll order a couple so I have one as a backup.

I’m not 100% sure but I’m thinking when the suck out the system with a honey wagon it may be the culprit as opposed to gravity draining.

 

[Lynn1130]

Here is the scenario where I get sewer smell back into the trailer.

The vent cover for the bathroom vent is open and the fan may or may not be running. In most cases it is worse if it is not. Another vent fan is running in the trailer. I usually have the FantasticFan on low going in the bedroom, which is next to the bath. I leave that on to vent the moist hot shower air out. At this point there are times when I get the smell.

There are several threads about this problem and all connect it to the unsealed area around the toilet vent that goes to the roof. The fan going inside pulls air from the toilet/black tank vent back into the trailer through the open bathroom fan vent.

Most cases this was solved by sealing the area around the black tank vent on the roof.

 

[RickL]

UPDATE - The wife did a load of laundry and the smell disappeared. So my assumption it is the Hepvo valve as Dan pointed out. When I get to Yuma for the winter I’ll pull the washer out of the slide and replace the valve. There is an access panel towards the floor so that would make sense. Originally I was thinking it was going to be a hidden Studor valve with no access panel but the one by the floor makes a lot of sense that there is a valve down there.

 

[JohnD]

Let us know when you get to Yuma...

I'll buy you a beer or three!

 

[Lou_and_Bette]

UPDATE - The wife did a load of laundry and the smell disappeared. So my assumption it is the Hepvo valve as Dan pointed out. When I get to Yuma for the winter I’ll pull the washer out of the slide and replace the valve. There is an access panel towards the floor so that would make sense. Originally I was thinking it was going to be a hidden Studor valve with no access panel but the one by the floor makes a lot of sense that there is a valve down there.

See Cookie's suggestion in previous response. Running washer through cycle would have added water to P-trap and stopped smell if that was the problem. I would wait to start tearing things out to see if smell stays away from just having the trap filled.

 

[CDN]

Just to add to the Washer drain smell. We don't have a washer but I primed the trap with water then added vegetable oil that does not evaporate. I then put a pipe cap on top to assist in keeping odors away.

Brian