Leak into wet bay when using black tank rinse and...

[kramocker]

Hello,
I’m always thankful to those that offer help and humbled by how much I don’t know.
Recently, I’ve had water in the wet bay, under two circumstances:
1. Allowing the gray and black tanks to fill rather high.
2. When using the back tank rinse (with the valve open).
Note that the water is dripping onto and off of the white “backer plate” that houses the hose fittings (please see pic).
I’m thinking, “This can’t be good”.
Thoughts? TIA

Cheers,

Steve

[ependydad]

I'm struggling following your description a bit. You're going to need to follow the water to find it's source. It sucks that you may need to tear into some hidden areas of the RV.

[kramocker]

Thanks. I’ve since discovered a few more “clues”.

We’ve been in the rig for two months. It seems that when the black tank gets to a certain level, we get a horrible smell in the bathroom. Since the toilet is well bolted to the floor and the bowl is holding water, how is this even possible?

But wait...there’s more.

The two time this has happened, I also had water in the wet bay.

Add to that, water also leaking into the wet bay, when using the black tank rinse.

I welcome any thoughts...

Be well!

[ependydad]

The smell is likely coming from the air admittance valve under the sink. These are cheap and easy to swap out (under $10 and no tools).

[5picker]

As mentioned, there are several things that can cause the issues you are referring to.

First... grey tank smells can actually be worse than black tank smells because black tank smells are typically masked by the use of chemicals where as, most folks don't put anything in the grey tanks to mask odors. There is an air admittance valve under the sink (usually kitchen) that vents the plumbing. Food particle build-up in the grey tank can stink to high Heaven. It is possible that is what you are smelling.

On the other hand, if the tank(s) have a crack or leak in any way, they can allow liquid to spill out and stink too.

For the leak when using the black tank flush... that system has what is called a anti-siphon/check valve in the plumbing that is often referenced as having issues leaking. it is usually located in the bathroom vanity (under the sink) and there are plenty of posts about it leaking when using the black tank flush. It could be that's what's dripping on the wet bay area when using the flush.

Here are photos of the air admittance valve and the black tank flush anti-siphon valve...

[kramocker]

Thanks for your comprehensive reply. Great points, all. Since then, I replaced the AAV’s on both sinks. I also changed the Black tank rinse anti-siphon valve.
Your assumption that we were smelling the gray tank was likely dead on. Who knew?
I still seem to have an issue with water getting into the wet bay, from what I assume to be the black tank and/or a related component(s). Here’s why:
The black tank was very full.
The gray tank was “open and empty”.
We could smell a faint version of the previous smell.
And...Water in the wet bay.
What could it be? Am I just letting the black tank get too full? I mean, it’s a safe bet that had I emptied it yesterday, I’d have had no smell/leak. Or, is some part of the tank or it’s components somehow “open”-
Thanks in advance,

Steve

[Reverse_snowbird]

This probably has nothing to do with your problem, but we had a leak in the pipe under the shower. The shower is between the toilet and the black tank.
While repairing the leak which went to the grey tank, we found that the black water pipe ran under the shower and was loose. If that had come loose, the water would have run down hill and filled one of our bays.
Probably not your problem, but I thought I'd mention it.

[5picker]

Typically, the black tank and associated plumbing are sealed with the exception of the roof stack vent. (cap)

There are multiple postings from folks who have used their black tank flush mistakenly with the dump valve closed, filling the black tank until liquid ran out the vent stack on the roof with nothing leaking inside. (well except the one guy who pushed the toilet valve to find he simulated Old Faithful!)

The toilet drain pipe and the vent stack usually have rubber like gaskets that seal where they go into the top of the tank.

Without doing some investigation as to whether the seals are misinstalled, or a screw or hole got accidentally drilled into the tank (been reported as have happened) none of us can really say with any certainty.

[ependydad]

Originally Posted by 5picker

(well except the one guy who pushed the toilet valve to find he simulated Old Faithful!)

I'll admit, I was flushing my black tank and came to the terrible realization that I forgot to set a timer. I went running out of the camper and as I did, I yelled to the family, "NO ONE FLUSH!!!"

I got lucky, no mess. But I chuckled at the prospect.