Horrible smell from RV toilet - any recommendations?

I run a bleach and Dawn solution twice a year in all three tanks. It kills any bacteria in them and keeps them from smelling bad.

Perhaps do not eat as many dishes containing cabbage, eggs, onions, etc, as well as certain varieties of cheese.:E

I had very good results from installing the 360 Siphon Vent Covers.

for the past 4 or 5 years, we have been using cheap liquid detergent and Borax, a cup of each in the black tank and the same for the gray tank. we add it each time we dump our tanks, about every 10 days, and have no problems with smells.

In our 8th year of full-time and have never used chemicals, just make sure there is some water in tank after dumping and generous water when we flush. We don't flush the tank every time either, just every month or so. All of the items listed above except chemicals need to be checked. The chemical is a deodorizer - covers up the odor, doesn't correct any problem and make it go away. Good luck.

nayther wrote:
I never looked under the sink for an air admittance valve and there should not have been one since there were vents. Just sold that one.

Without an AAV under the counter by the sink, the water would be siphoned out of the sink's trap EVERY TIME you ran more than a trickle of water. The AAV is to break the vacuum that the flowing water otherwise would generate so the water stays in the trap.

DutchmenSport wrote:
Ah, and those that say they never have smells and no need to clean their tanks or rinse them out, well ... here ya go! If they didn't stink, then why all the chemicals, flushing and everything else that's done to keep smells at bay?

I don't think those of us without smells are saying you don't have to clean your tanks. We're stating from our experience, deoderizors aren't needed if you use plenty of water. When we dump we'll 'sometimes' use the tank flusher (not if there's a line at the dump station). It's not needed every time. We also add a bucket or two of water to get things going. Then begin the drive where that water can 'somewhat' splash around. When we use the black tank flusher & if there's no one behind us at the dump station, we'll use it for a long time while it's draining. That's sufficient every so often. You'll never get the tank really clean. :)

As for as the deoderizors they sell.... how many things are on the market that you don't need? It's called 'sales/gimmicks'.

Thank you all for your advice. The humidity and heat have been terrible in WI this week which has made the odor worse. We have owned several other travel trailers but don't recall it being this bad. The tank is "clean", but we will look into trying some of your suggestions.

After you (finally) get it fixed, please report back as to what worked. It may help someone else in the future.

We had a dometic model 300 that was know to be defective from the factory and even though it was 5 years old they stood behind there product and sent us a new one. Our whole camper smelled like an out house. I flushed the black tank and put all the chem I had In There and it still stank. "Stuff" was leaking between the outside and the inside of the bowl.