Sewer Smells

Do you keep water in the toilet bowl?
There's only two ways this can happen, the smell is coming thru the toilet but if you have water in it I would rule that out and two... thru the vent pipe on top of the Coach. Perhaps if you have a fan or the A/C running your sucking that perfumed air inside?

I recommend you dump - refill with water and dump again. If you use a solution that doesn't work well try RIDX fro RV! We did and it is super!!

Hoppy dumps and sorry for your troubles. :E

p.s. I suspect there is **** left over from each dump and RID-X for RV will help.

I'd check the ball valve seal on the toilet first thing. Second, sometimes the bathroom sink is plumbed to the black tank... and it usually has an air admittance valve. That is likely shot, so replace it, or if one is a plumber, replace the trap with a HepVo waterless trap, which not just keeps smells from coming out, it allows air to come in the drain to equalize pressure.

It is definately coming from the toilet. And no we do not leave any water in it? Should we be Halibut214? We dump, run fresh water in it and then dump again. But we dont leave any water in it? We have ordered the Sewer Solution, so hoping this will help "clean" it out.

Do you think the odor is from, sorry, you or leftovers from previous occupants? Filling it up with just fresh water and then dumping might help you figure out whether the odor is from new "stuff" or old stuff.


When we got our gently-used new-to-us motorhome I bought a couple pints of bleach and one of those Camco Holding Tank Spray Wands at Walmart. I sprayed the black tank, filled it, then added the bleach and waited.

You might try that, if the RidX doesn't clean up what ever is down there.

tnmotonana wrote:
It is definately coming from the toilet. And no we do not leave any water in it? Should we be Halibut214? We dump, run fresh water in it and then dump again. But we dont leave any water in it? We have ordered the Sewer Solution, so hoping this will help "clean" it out.

I always leave a little water in it. If the water slowly disappears you have a bad seal and will need to get it fixed. Next time you dump fill the bowl before hand and see if you still get the smell. Based on what your saying I don't think you will. You can rinse and flush the black tank all day long but that is not going to fix your problem, but only mask it.
Let me also add the fact that your dump hose is going where... a tank that's full of sh**! If you have air coming up around the seal on your toilet, guess what.

When you flush toilet a little bit of water should flow into bowl after ball/blade closes.
This water provides a vapor barrier because RV toilets do not have a 'P' trap like residential toilets do (built into toilet)

If water does not stay in toilet then bowl seal is not holding/sealing off like it should.
Dirty/crusted up...............needs a good cleaning

If water doesn't stay in toilet bowl you should be having odors from black tank all the time......not just when dumping.

Are you running bathroom exhaust fan when dumping?


Having had a pull behind for years you should know about water in toilet bowl.

I would ask my trusty nose to do a bit of investigating. If the odor is coming from the toilet, then where at the toilet? And if there is not any odor other than during the dump, then see what could cause an odor at that time. Odor from the tank is getting into the toilet area and during a dump your tank could be filling with the sewer gases from the dump station - but should be vented through the vent stack and not into the toilet area.

I dont think we really noticed it in the TT because we were not in the trailer after dumping Old-Biscuit.
And yes the toilet bowl does hold water but I always empty that as well. And run water continuously after he dumps. But I dont leave water in the bowl Halibut214. So Im thinking maybe we are doing it wrong. Leave the toilet closed while he is dumping with water in the bowl. Thanks so much. Will give this a try.

Old-Biscuit wrote:


If water doesn't stay in toilet bowl you should be having odors from black tank all the time......not just when dumping.

Not necessarily. When you lift the lid at the dump station you are more times than not greeted with gas. The gas rises up through the hose, into the holding tank, through the bad seal and right up your nose.