Sewer smell in RV

[Durhamcutter]

My wife says she smelled sewer in the 5er when it sits up for any given period of time, but when we are using it after a day or so the smell disappears. Has anyone else had a similar problem? Have tried to find the problem but have had no luck. Any help would be appreciated.

[Spleenstomper]

I started using the "geo" method of putting water softener + laundry detergent down the toilet when the water will slosh around (before and after a camp/dumping for example) and I have noticed the "cabbage" smell is ours has been much less offensive, supposedly you have to do this a few times before it totally works, so we are hoping the smell will be totally gone next time.

[slarsen]

Under-sink valve: they are really cheap valves, use only a little piece of rubber that resembles a chunk of inner tube to keep fumes from rising into the trailer. Unfortunately, the flap is fighting gravity along with air currents.

I replaced mine with a higher quality unit that I got at Menards. But the same or similar valves are available from Amazon. Expect to spend about $20, not the cheap replacement that costs around $5. Or expect to get recurrences from time to time for no apparent reason.

[Paul_Clancy]

Yep. I vote for the under sink valve. Mine was loose on the new trailer and went defective on the old. Found a new one at Home Depot under $20.

[2112]

I had this problem in my new FW. The flapper valve under the sink was loose. I hand tightened it and the smell did not return.

[JohnD222]

If it is evaporation of the p traps, a little Wesson oil or other cooking oil in each drain and the toilet will greatly slow the evaporation process.

[SooperDaddy]

Some RV's don't have roof top vent pipes from each drain into the holding tank for grey water waste from sink, shower etc.

This explains what a "under sink flapper Valve" is and how to replace it.

Everything about RVing explains it!

[Durhamcutter]

Thanks I will give that a try, I figured it was something simple, thanks again.

[Artum_Snowbird]

A very common problem. Just go out to your RV when it sits and put a little water down the drain once a week. The traps will dry out and allow grey water smells in unless you do that.