black tank odor

it may not be the black tank. sometimes when the sink and shower pee traps dry out the grey tank smells just as bad. there is also a vent under the sink that dry's up and needs to be replaced. try the water in the traps first. that is the cheapest cure to try.

Agree with Oregon- it could be the gray tank and I could not believe how bad it got. I would reccomend that every RVer carry an extra anti siphon cap with them- We have never had a problem with our black tank, but sure did with gray. We were told it is more important to treat it, than the black, because it doesn't get flushed. Not sure if that is true, but YIKES, it was bad. We went out and bought backups for the other two sink traps.