Black Tank Odor

[garywilson]

Check for recall or complaints on your particular toilet model number.
Some leak and hold water inside toilet?

[Bonron]

Originally Posted by Warhorse6

I suspect you may have a faulty air admittance valve. check underneath your sink in the bathroom for an air admittance valve. That’s what gave me the smell in our rv, even though I religiously rinse the black tank after each draining. The valve is usually black and sits on top of a vertical pvc pipe. You can buy one at lowes or Home Depot for under $9. Hope that resolves your issue.

Bingo!! Those valves do go bad from time to time. They’re easy to screw off and you can’t find them at Lowes or Homer’s depot.

[J. W. Hyde]

We had the same problem with our first MH--Faulty vent---replaced it and no more stink !!

[cokerstrom]

I've been battling an ongoing intermittent stink issue for some time now, but in my case it seems to come from the shower area (as near as I can tell). Does anyone know if there is a AAV located on the shower stack in a '16 Entegra Aspire? And if so, where?


Thanks!

[Marshalone]

We also have this issue from time to time. One of the problems I find is that there seems to be 'stuff' sticking to the sensors. I never get an empty signal on my sensors so I know there is stuff in the tank that should have drained out. Next trip in a couple of weeks we're going to put a box of Borax in with some warm water and let that slop around for the trip to the coast. I have heard that works. We'll see. Happy camping.

[twogypsies]

Originally Posted by Marshalone

One of the problems I find is that there seems to be 'stuff' sticking to the sensors. I never get an empty signal on my sensors so I know there is stuff in the tank that should have drained out.

If your toilet is sealed there will be no odor coming from the tank even when the toilet is full of c**p! Something stuck to the sensors wouldn't create a smell. As I stated above, we never used anything in our tank and never had a smell.

[shootist]

The air admittance valves are only on the grey tank. Possible your kitchen sink is on the black tank though. The valve I posted is the only black tank valve in most rvs. It will cause your exact symptoms. Tank clean, no smell, about as soon as you use the toilet the smell starts to permiate the entire motorhome. If you have a tank flush system I am pretty sure you have that valve. When mine was bad I had cleaned the tank with borax, dawn and a 20 mile drive to change the dump valve. The water was sparkling clean after that and still the smell came right back. There are two valves in it. The horizontal seals off the black tank, the upright is an air break. It closes with water pressure and the other opens. So if the horizontal leaks air at all, there is nothing to stop it from going in the coach. I've had the air admittance vavles go too. And if you are rinsing food down the sink, especially vegetable matter your black tank smell will about make you puke when those valves leak. But it's a very different smell than the black tank.

[Dusty Dude]

In my previous class C we started getting a sewer smell each time we started a trip. I tried pretty much everything mentioned in the previous posts with no result. I eventually found the kitchen sink drained directly into the gray tank, but the connection at the tank was broken. I realigned the pipe/connector and applied a thick coat of JB Weld. The smell never came back.

[tdelong]

Originally Posted by tdelong

We bought our Class C in December of 2020 and take it out about once a month all year long (we live in Texas). However, we are having issues with our black tank odor. We use Happy Camper, LOTS of water, and flush the tank 3-4 times every time we dump, then load it back up with water and Happy Camper. When we pick it up from storage, it's fine. After one day of use, it smells like an outhouse - no matter what we do. We've checked the vent, by sending water from the roof, and it lands in the tank with no visible leaks. I'm at a loss as to the problem, and we are taking a three week trip in July. I can't live with an outhouse smell for 3 weeks.
Any suggestions about what I could be missing? Or another way to check the vent? I'm afraid that it is venting into the bathroom, but I thought our trouble-shooting measure proved the vent was functional. Help and advice would be so welcomed.

Update - we found the culprit. It was the Dometic 300 toilet itself. We took it out, cleaned it, and re-seated the seals. No more odor!

[GPCPL]

Originally Posted by tdelong

Update - we found the culprit. It was the Dometic 300 toilet itself. We took it out, cleaned it, and re-seated the seals. No more odor!

Glad you found the problem and thanks for reporting back.

[garywilson]

Originally Posted by tdelong

Update - we found the culprit. It was the Dometic 300 toilet itself. We took it out, cleaned it, and re-seated the seals. No more odor!

Yours is not the first... BIL changed his twice, gave up.
Something inside was retaining water, I think.....