Grey tank Odor inside coach

[bdickson]

In the last few days, we have noticed a distinct grey tank smell (rotten eggs) inside the coach. It is happening whenever we run a lot of water into the grey tank at once, such as rinsing dishes or taking a shower. I went on the roof and checked the vent, no problem there. Also did "sniff tests" under the sink and in the bathroom. No particular odor there. It almost seems like its coming back through the P traps. Any thoughts out there?

[Full.Monte]

If your P-trap is working, it shouldn't smell, UNLESS it's bacteria in the P-trap.
Try a little chlorox in the trap/tank and see if it goes away. It will happen on almost any rig if left to sit too long with bio material in the tank.

[BFlinn181]

You probably have vents on the sink traps. These are supposed to be one way valves, (letting air in to prevent water in trap from being drained) but they sometimes fail. You can test by putting a plastic bag and rubber band on to see if odor disappears. If it does, go buy a new one at Lowes, Home Depot, or plumbing supply. They are cheap and just screw on.