Sewer smell from roof vent (UPDATE)

Yep, I have replaced both AAVs in my RV, and keep a spare one in the basement. They are cheap enough.

When we bought our Winnie we got some horrible odors from the black tank and probably some from the gray tank. I repaired the biggest culprit, the worn flush ball valve seal and installed two new AAV's. They are mini-vents by Studor. Not cheap but work better than those $1.89 Camco things.

We're taking the 16 yo DGD to the beach next week and I'll dump every other day and see if I still get any odors when dumping. I inadvertently opened the flush valve yesterday while the exhaust fan was running, there was almost no odor. I think all the flushing and cleaning I did to the black tank was partly the reason it does not smell very strong.

I have the Cyclone on both the black & grey tank vents, as at times, the grey can smell nearly as bad as the black.

We have replaced both of the air admittance valves under the sinks a couple of times now. You can always tell when one of them is bad as you start getting the odor. Glad you figured out the problem.

Well I was convinced the smell was coming from the black tank vent and then coming back in the bathroom roof vent. After doing everything to eliminate the back flow nothing helped.

I traced the smell down to a defective vent under the kitchen sink. All the smell was coming from the kitchen grey tank. It would be worse with the bathroom roof vent open since it would suck air out the kitchen flapper valve.

No matter what you do, the black tank vent will still be right beside the bathroom vent. The only real solution I can see is to keep the bathroom vent closed unless its exhaust fan is running.

Have you thought of opening windows and using the fans to exhaust out.

Turtle n Peeps wrote:
I would just throw a bottle of blue in the black tank. No smell venting off, no smell when flushing, no smell while dumping.

I can assure you that while chemicals will cut down the odor, there is no such thing as an odor free black tank during use. Fortunately the majority of the time I could also make the claim that mine didn't stink but I bet if you dumped yours at your feet you might sing a different song.:B

Installed one too.

I would just throw a bottle of blue in the black tank. No smell venting off, no smell when flushing, no smell while dumping.