Odor When Dumping Tanks

[Montana_1235]

When dumping the tanks over the Columbus Day weekend I noticed a sewage odor in the camper and didn’t know where it was coming from. I had not dumped the tanks since we boondocked a few weeks ago and thought that was the reason but still didn’t understand why the smell was coming into the camper. The black tank was 2/3 full, the galley was full and the gray was full when I dumped them. I dumped in the same order, Black, Galley, and Gray as I always do.

After wondering about where the smell was possibly coming from, I remembered we have a Washer / Dryer. We haven’t used it since we were at the beach in July. The smell was stronger in the bedroom than anywhere else so I thought it could have been the W/D drain. The fact that it wasn’t used since July, combined with the bouncing that happens in the rear made the level of water in the trap disappear.

We have the 3685FL. The W/D is located in the bedroom in the rear of the coach. There is no valve prior to the main drain. It is open all the time just like a house. The trap is supposed to keep water in it to prevent sewer gasses from coming through. In his case it didn’t.

I ran the W/D through a cycle to fill the trap and that corrected the problem. No vulgar smells occurred when I dumped the tanks afterward.

I don’t know if anyone else has run into this problem but the better fix is to install a valve to shut off the flow just like the rest of the tanks. Just have to remember to open it before doing a wash! That will be one of my off season projects.

Happy RVing!

Bill

[OntMont]

Hi Bill and Pat.

I'd give some second thoughts about that valve. I think the potential for a really serious flood outweighs an occasional bad smell. Now that you know the problem exists, you could just add a cup of water to the trap as required. Maybe plumb in some little filling tube if it is hard to get at the drain. Just my 2 cents worth, its your choice.

[BillyRay]

it's possible that during trave the water emptied out of the trap, thus letting air flow through.I wouldn't change anything, just try adding some water in the tub and run it through a spin cycle...see if that helps...it may be the easiest solution.

[Glenn and Lorraine]

More than likely what happened is called evaporation. The bouncing would cause some loss but evaporation is the main culprit. It doesn't take long for the little bit of water in a trap to evaporate. As the others have suggested, every so often, add some water to the trap. And as OntMont said "I'd give some second thoughts about that valve. I think the potential for a really serious flood outweighs an occasional bad smell." Forget to open the valve and a bad odor will be the least of your worries.

[Northstar]

What a great post. Nice info to have. Happyrving....

[Montana_1235]

Thanks for everyone's imput. You're probably right about not putting a valve inline. I'll just run the washer through the rinse cycle to fill the trap. That will correct the problem.

I talked to a friend that is a certified RV mechanic about the washer drain when we first got the camper. He said that some manufacturers put the valve in and some don't. He's seen several overflow because the valve wasn't opened prior to washing a load.

Again I thank you all for your advice. A little smell once in a while is much better than a flooded camper!
Bill

[sreigle]

Bill n Pat, thanks for the post. A couple of times after some particularly long driving days on really bouncy roads we've had that sewer smell. Usually it's a trap lost water in one of the sinks of the shower. We run water into the traps and get rid of further odors. But I never thought about the washer trap. I'll keep that one in mind.

I have enough trouble with the slide valves we already have, with remembering to open them before the washer runs, that is. We (meaning I forgot) once flooded our bathroom and basement because of not opening the gray valve. Second time Vicki saw it backing up into the shower so we avoided a flood that time. It's easy to forget. Now Vicki asks me if the valves are open then asks me if I'm sure and then asks me if I'm positive. Then I go doublecheck.