Odour is only present in basement of 5th wheel. Not sure if black or gray, not terribly offensive so thinking gray. Can see top of tanks. Connections seem secure. No liquid anywhere.
Gray: Two incoming pipes, one from bathroom and one from washer (not installed and has a waterless trap)
No vent stack directly from tank, shared with drain from sinks with AAV between. Shower drains directly to tank.
Trailer in operation 4 years without this issue.
Vent stacks have not slipped.
question: should I get an odour on roof constantly or only when in use?
Iโm by myself so canโt check black vent, but I smell nothing on roof when sinks and shower running.
Any other suggestions welcome.