Gray Tank Odor / Black Tank Odor

[Mosnowman]

I have a 2018 3721RL and have some new odor problems popping up. No problems when new, started roughly 6 months in.

Gray Tank: I keep tank closed and only open when dumping. Here is what started happening after DW completely filled (over filled ) the gray tank. It now occurs even after dumping. Pungent Gray Tank Odor is coming from shower drain. I put a red solo cup over drain, and that works as a temporary solution. Stops odor.

Black Tank: Only open when dumping. When flushing toilet there is an intense black tank odor that fills bathroom. Happens without fan running. It didn’t use to smell when flushing.

Thoughts?

[scattershot]

Blocked vent tube?

[DadsHemi]

Sounds like a blocked vent or vents, also sounds like the flap in the shower drain is not working properly.

[Rondo]

Steve-- First of all are you using anything in the tanks for breakdown of solids, especially the black tank but it can be used in the gray tanks also. Second, when you dump the black tank are you back flushing it also with the backflush for the back tank? It does sound like the vent pipes may be blocked but it could be just that bacteria has built up in both the tanks to cause this problem. The shower gray should have a backflow valve in the drain pipe that my need replacing or the gasket in it may be bad or reversed it's position. This could cause the problem also for that tank but the bacteria build up sounds like the culprit to me in both tanks. I use Happy Camper in all my tanks and haven't had a problem with smell or solids at all on either one of my rigs.

[DadsHemi]

We use the Happy Camper Cem as well, best I’ve ever used.

[Kyle and Lisa]

We started using the TST treatment from Walmart after noticing an odor when running the ceiling vents, we use it every time we move and have not noticed an odor since, and we use it in the grey tanks as well. Recently after draining the main grey tank it went from 2\3 to empty after seeing at 2\3 for 11 months when we know it is empty !

[DQDick]

Happy Camper for us also. The shower drain problem sounds like what Rondo indicated. In the drain line below your shower is a HEPVO valve. That uses a membrane to stop oders just like a P trap uses water. If overflowing the tank reversed the membrane that could be your problem.

[BuilderBob]

Sound like you have a problem with the HEPVO valve in the shower drain it replaces the pee-trap that most drains have there is a one way rubber valve that can get worn or damaged and not stop the tank oders from coming in. If you are getting oders from the black first of all does the toilet hold water in the bowl if not that would be the first thing you need to fix the water keeps the oders out. The next is what kind of tank Cem! are you using Happy Camper is the best out there you can buy it on Amazon.

[Texan]

I use happy camper also with no odor. I don't need some brand that is lemon fresh or what ever the flavor is of the day. The best smell is no smell period. Rondo may be correct in that bacteria may have built up in tank. Happy camper makes a product as well as others that you can pour down the toilet and fill about half full on your next travel day and let it slosh around while traveling. Sometimes the tanks just need a good cleaning. If this doesn't work then i would look at other options that have been stated on this forum. Good luck.