Bathroom odor only after motor home has been driven?

[realdeal1003]

Hi guys. Here is the issue. After having had the black tank uncloged/flushed, there is a waste odor ONLY after I drive the motor home. If the motor home just sits without driving, there is no odor. Has anyone had this happen? Any and all input would be greatly appreciated. Thank You Louie

[cummins2014]

Boon Docker wrote:

wildtoad wrote:
Pour some water down the shower drain and sink to fill up the p-traps which are used to prevent odors.

That would work just fine if there was black water in the grey tank. :B

Those grey tanks don't exactly smell like roses, they can be pretty foul.

[JKJavelin]

Nomadic Fanatic
Looks like he had the same problem.

[realdeal1003]

Hi guys. OP here. First, I want to thank everyone that responded. Went to an RV place here in Yuma and we decided to start with the vent itself. As the days went by, the odor has definitely gotten less? Rather than pay the RV place, I decided to let more days go by and see/smell if the problem goes completely away. Why spend money exploring if, hopefully the odor goes away. I let the black tank go to about 3/4 and I have a feeling the entrance to the vent was cleared some from the additional sloshing around. Of course I don't know for sure. Again, thank you for the many responses. Louie

[covered_wagon]

I wouldn't want that cyclone vent standing up so high so as to get snagged on branches. That can ruin a roof area if hit.

Here Is Your Problem.....

I think your problem is from the rv builder who usually drills too big of holes for the size vent pipe thru the roof. It gets covered up by the vent cover so you have to pull the vent covers to look down inside and you can see the problem. The sewer smell gas has access to GET down inside the cabin because it isn't sealed around the pipe to the roof down inside there. The covers cover this problem up very nicely so you have to pull the caps to see down in there.

[jerryjay11]

Had same problem with a class B motorhome when I drove with cab windows open. I chose to close the windows, but that cyclone vent as suggested would have helped.

[afidel]

Yup, coworker had that problem with his TT, bought a cyclone sewer vent, never had the problem again. For <$20 it's certainly worth a try.

[Boon_Docker]

Yes, it does smell as bad, but a completely different smell. Not hard to tell which is which.

Quote from OP "After having had the black tank uncloged/flushed"

[Bobbo]

Boon Docker wrote:

wildtoad wrote:
Pour some water down the shower drain and sink to fill up the p-traps which are used to prevent odors.

That would work just fine if there was black water in the grey tank. :B

Gray water smells as bad as black water.

To the OP - my two solutions have already been mentioned. Be sure the vents on the roof are closed. When you drive with them open, the venturi effect causes a vacuum in the MH and can draw odors out of the tanks. And, be sure that all of the traps, sinks, toilet and shower have water in them.

[malexander]

The water is probably sloshing out of the traps while driving. The grey tank will have a sewer/stale water smell to it. I doubt if it's the black tank you're smelling. YMMV

[Boon_Docker]

wildtoad wrote:
Pour some water down the shower drain and sink to fill up the p-traps which are used to prevent odors.

That would work just fine if there was black water in the grey tank. :B

[cwit]

One other thing that caused my same problem.. there is a rubber seal under your toilet that can allow sewer gas to escape while driving.

[SDcampowneroper]

If you have roof vents open it creates a vacuum in the rig. Many rigs are built with ' pop vents ' instead of plumbed waste tank vents. You would see that under the sinks, to the sides of the P traps. Popvents are supposed to work only when there is lower pressure in the tank than in the house, Maybe yours is acting both ways?

[wildtoad]

Pour some water down the shower drain and sink to fill up the p-traps which are used to prevent odors.

[Fritz_H]

First thing to try - are you driving with any of the roof vents open? If yes, try it with them closed - I bet you'll have less odor.