bad odor

I had a similar problem earlier this year and lived with it for most of the Summer. Last year we had sewer smells but this year seemed far worse. During our trips, I would smell this sewer odor when we were camped, stopped, moving...just about anytime. I drove with the windows open, closed, and in between. I put oil around my toilet seal; made sure my traps had water; checked all the valves; checked the air vents. Looked for dead mice and bad food. I talked to other RVers at campsites to see if they had similar problems. Nothing worked.

I finally saw an ad for the Cyclone Sewer Vent and installed it. I really didn't think it would work but for $15 I was willing to take a chance. I was desperate. It took about an hour and you'll need dicor sealant. But what a difference. We took a 2 week trip and NOT ONCE did we smell any sewer odor. I drove fast and slow, stopped and camped...and no smell. It may not be your solution but it worked for us. I've bought many items for the RV in the 9 years I've been RVing and only this Cyclone Vent and the Door Handle Cross Bar have I enthusiastically endorsed.

don,t have a washing machine, but will be checking all the p traps and flushing out the holding tanks.

Harvard wrote:
In all likelihood there is a P trap but it has never been filled with water. OP does not specifically say he has a washing machine that is used regularly to keep a P trap filled.

As I said, this is probably not the same problem the OP has.

In my case there is no "p" trap. I even poured water down the pipe the first time I noticed this problem. Another poster, who identified a similar problem a few months ago, said his washing machine went straight to the sewer without passing through the gray water tank. I have had three units with washing machines and they all dumped into the gray water tank.

Harvard wrote:
Seems to me a washing machine drain without a P trap would be against some plumping code, RV or not an RV.

I'm not sure what the status of building/plumbing/electrical codes - as applied to RVs - is. That said, I wouldn't want to have an RV that didn't meet codes - they were developed with safety in mind and do a good job of keeping things safe. :) I know there are some RV codes, but don't know if they are voluntary or mandatory.

In all likelihood there is a P trap but it has never been filled with water. OP does not specifically say he has a washing machine that is used regularly to keep a P trap filled.

Quite possible, but it's an easy fix to add water. I have a bathroom that's not used often and some summers I lose water in the traps if I don't run some in the sink and tub. That said, in my RV, a dead mouse is the usual cause of a bad odor, and that smell is almost identical to the sewer odor from the trap that dries out.

Seems to me a washing machine drain without a P trap would be against some plumping code, RV or not an RV.

In all likelihood there is a P trap but it has never been filled with water. OP does not specifically say he has a washing machine that is used regularly to keep a P trap filled.

mikestock wrote:
The sewer odor backs up through the washing machine stand pipe.

I don't have any experience with washing machines in RVs, but might want one some day. Don't they have P-traps and vents installed, as in a home? Or do they use air admittance valves/a.k.a. "cheater vents"? Or nothing? I've got enough trouble with the DWs sensitive nose finding disagreeable odors from some mouse nest I could never locate in the wall. I don't want sewer odors, too. :)

No. Actually I meant what I said. The smell coming from the sewer comes, unrestricted,to the top of the stand pipe for the washing machine.

mikestock, I hope you don't mean you leave your black valve open. That should be kept closed until ready to dump. If open, the liquids will all drain off leaving the solids to dry out and you will eventually have a pile up and clog. Hoping that's not what you meant.

If your problem is there full time this won't apply, but it may be useful to somebody. I have had a problem when camping with sewer hookup and gray water dump valve open. The sewer odor backs up through the washing machine stand pipe.

Battery -- or how about a dead mouse somewhere? We had one in a wall once and the smell just got worse. We found it with a mirror in a wall between the bathroom and the washer/dryer closet but couldn't get to it. Opened containers of Mr Clean with frebreeze and put in the closet until it finished stinking (about 3 weeks). Hope to never have that again!