Terrible smell

[daniel723]

There is a terrible smell coming from under our bathroom sink and we can not figure out what it is. So far the things we have tried:
Replaced Mechanical plumbers vent
Replaced toilet floor flange seal
Got on roof and opened all vent caps to check for plugs (none)
Made sure all of our traps were full of water

It is a 2013 Salem 27RKSS. We don't know what to try next but something has to be done....any help appreciated

[dalford]

Welcome to the forum1
Do you mean air admittance valve?
Do you have a black tank flush?

[daniel723]

Thanks!
I think air admittance valve is another name for a MPV. What is a black tank flush?

[dalford]

Originally Posted by daniel723

Thanks!
I think air admittance valve is another name for a MPV. What is a black tank flush?

Is there a connection to hook water up from outside to flush your black tank?

[daniel723]

No, there isn't any external flush like that.

[AFDON]

What does it smell like? Sewer, dead mouse, moldy, wet shoes? Worse in hot weather or when raining? Does your cabinet have a floor in it above the main camper floor? Thinking maybe a leak under the floor has soaked into the insulation and you have something going on there. Don't know your rig. Do you have an access panel under your shower, what commode do you have? Some of the commodes have developed leaks and trap urine. That gives a bad smell. More information you can give, the better we can help. Let us know, please.

[oxcamper]

Our 282RK had the black tank slip off it's mounting flanges causing a separation of the toilet pipe into the black tank.
The smell of sewage was coming out from under the sink where the holes for the water hoses and drain was.

Unfortunately the only way to determine if this is your case is to take off the underbelly cover to see if all the pipes are connected.

[daniel723]

Afdon - It smells like either black tank or gray tank. I have heard the gray tank can actually smell worse sometimes but I don't know. It does not smell like a dead mouse to me at all. The camper is very dry and in good shape. There is a panel under the sink that exposes more plumbing and everything looks very clean under there.
There is no access under the shower that I can see. It is a dometic 300 toilet. I changed out the floor flange seal and everything looked dry, clean (as much as the bottom of a toilet can look clean) and nothing seemed out of place. When I changed the seal there was hardly any odor at all actually.

Oxcamper - We hardly move our trailer as it stays on our property a couple hours away. I don't think shifting would be an issue. I will definitely keep it in consideration though. When I changed the floor seal everything looked ok where it connects. It does seem like the odor is coming through the holes where the plumbing comes through though. Not sure how else it would be focused under the sink

I ordered another mechanical plumbing vent incase I bought a bad one the first time? Who knows, getting desperate now.

[oxcamper]

Understand.

just some background, we were seasonal and left our unit in place for over 5 years, however during that time we took one trip to the Smokies. after that, and there was no significant bumps or rough roads, is when the odor started.

it's just something else to consider, as the tanks on our unit are held in place with minimal supports. It may not be the case with your RKSS, but the units are somewhat similar.

I hope you find the source and cause .

[AudiDudi]

There ar eknown issues with the Dometic 300. Search the forums. Here's an old article:


https://www.rvtravel.com/got-a-smell...e-the-problem/

[Reverse_snowbird]

Most showers have an access panel in front near the floor.
Do you use rv tank treatment in the grey and black tanks? They have some all natural treatments if you don't want the harsh chemicals.
I'd try treatment and flushing and if that doesn't work, look for a critter that's entered through a vent or pipe.

[daniel723]

I will look into the dometic 300 issues.

I will look again for a access panel to the shower, maybe it's there and I over looked it.

I do use a really nice power blue enzyme tank conditioner. I think my next step is to fill up the tanks completely and add a cup of that to each tank and let it sit for a week or so. Maybe there is just a really overpowering decomp issue that needs to be beat down.

[AudiDudi]

If the issue is the Dometic 300 series seal, adding stuff to the tanks will not have any effect. The Dometic 310 is a nice upgrade and hopefully you can get one for free. I paid a tad over $200 for my 310, but I was not replacing a 300.

[AFDON]

If very little odor when changing that commode seal, I think that would point me to the gray tank. Yes they can be VERY smelly! Have you looked under the rig? Do you get any smell at all under it? I'm thinking a bad gray joint or even a pipe that has failed.



Might try filling both tanks and adding some septic tank treatment to both. Fill all the way and then let it set for a few days. Drain, rinse and let us know if it helps.

Good Luck

[dalford]

Originally Posted by AFDON

If very little odor when changing that commode seal, I think that would point me to the gray tank. Yes they can be VERY smelly! Have you looked under the rig? Do you get any smell at all under it? I'm thinking a bad gray joint or even a pipe that has failed.



Might try filling both tanks and adding some septic tank treatment to both. Fill all the way and then let it set for a few days. Drain, rinse and let us know if it helps.

Good Luck

This reminds me when I had a sewer smell and I took my 5th wheel to Orvin. He filled every tank full until the water came up in the sinks, tub and toilet. He then looked for leaks. He did not find one by that method because the leak was high up in the stink pipe In the wall. You might try that if.you,have a way to dump tanks when done.

[{Tpc}]

They make gray water treatment. Over the years I’ve smelled some nasty gray tanks from other campers/friends. Smells a lot like rotten eggs usually. I’ve loaned them (ok given) some gray water treatment stuff and that typically clears it up within one treatment.

I think it’s from food particles which get washed down the sink occasionally when doing dishes. It doesn’t always smell inside the camper but sometimes it does and I assume it’s from the air admittance valve though admittedly (lol) I’m not 100% sure how that is supposed to work.

[Mjseno]

I have a foul odor which seems to be after I run the hot water heater. It doesn't seem to be at all coming from the bathroom or the sewage. Any ideas

[rjshiflet]

Originally Posted by oxcamper

Our 282RK had the black tank slip off it's mounting flanges causing a separation of the toilet pipe into the black tank.
The smell of sewage was coming out from under the sink where the holes for the water hoses and drain was.

Unfortunately the only way to determine if this is your case is to take off the underbelly cover to see if all the pipes are connected.

This same thing happened to us with a Columbus fifth wheel. It drove us crazy until a very adept repair guy figured it out. It was evidently the fault of the factory - they simply didn't cut the rubber sleeve long enough and after a little use and some bumpy roads, it slipped off. It was replaced with a new rubber sleeve long enough to grip properly and stay connected. Problem solved.