Stinky smells

[Gcoupon12]

We have a 2021 Montana High Country 295RL and when ever we are at a campsite for several days and it's really hot outside, we start having a sewer odor coming in at the door and in the bedroom. We flush the black tank every time we dump until just clear water comes out. But we still get the odor after camping a few days. Not sure if it's coming from the black tank or not. Please help.

 

[AZ Traveler]

George,

Several things to check. You could have a leak out of one of your tanks or the vent to the roof. Don't rule out a grey tank issue. Keep your tank valves closed until you are ready to dump - this will prevent smells from the campground sewer system from migrating back in the camper.

 

[Gcoupon12]

We keep all the valves closed until we dump, we've been camping for years and never had this problem. We've owned four travel trailers, four fifth wheels and two motor homes. Right now we have been at a campground without full hookups for a week with temps in the mid 90's and started smelling the odor after the third full day.

 

[jsb5717]

Have you checked your Air Admittance Valve under your kitchen sink? We were getting the “sewer” smell as well. We replaced that valve and it went away. Not really sewer, though. Gray tank smells can be as bad.

Does your bathtub use a p-trap or a one-way valve? If it’s a one-way valve going bad you could be having the same result.

Beyond that, if there’s no evidence of any tank leakage, you might need to get a boroscope and look down a couple of tank vents from the roof to see if you spot any voids…especially where they connect directly to the tanks. Who knows what might have been missed in production. A loose vent connection wouldn’t produce an obvious leak but would allow gasses in the rig.

 

[Daryles]

Check your "air admittance valves" under both your sinks. Put a baggie over them and seal it with a rubber band. If the smell goes away, the valve is bad. Replace it. Local hardware store.
Also check your pipes going into your tanks.
Take down the basement walls and verify the pipes are properly inserted into the tanks. Give them a wiggle.
This guy had smells and found his vent pipe was not connected into the tank properly.

 

[foldbak]

I have the same RV and problem. It's only a problem in hot weather. It was an item on my 1 year warranty list. I was told they can't find the problem. 2 weeks ago I went to my service manager and told him he needs to fix it! Can't deal with this any longer. He agreed. He told me it's most likely the vent connection to the black tank. It goes in the shop in a few weeks. The odor is coming from the step vents.

 

[DutchmenSport]

It might not be your camper at all. Is there an underground sewer pipe running near your camper, a sewer hose connection, or a campground sewer vent near you.

We were once parked at a site (private campground) and had sewer smells come and go. I couldn't find anything wrong with the camper. After a few days I asked the owner of the campground if something was going on with the campground. He informed me we were parked right beside one of the sewer vents, and when several campers were running water at the same time (or dumping at the same time), odors would come out of that vent. When we left that campground, we never had that problem with smells again.

 

[LeftOverParts]

Writing to say thank you. Did the baggie test today as mentioned above by Daryles for an AAV under the kitchen sink and it worked to diagnose it as bad. Found a replacement at Lowe’s. Always appreciate all the knowledge and tips found here!

Edit: Adding a picture of the rubber seal in the valve. Looks like it’s cupped and lost its ability to seal. Some dust build up on the other side as well.