Grey water in Shower Pan

You have a junction somewhere from your kitchen and bathroom sink and shower drain.
It sounds like it may be partially obstructed below that.

Ours backed up at a site w/o sewer h/u. Tank indicator said tank was only 1/2 full but it was actually full. I have not had the tt long but have learned not to believe the tank level indicator. Dumped tank and no more problem...at least that trip.

Need to know kind of RV you need help on. Make, model, year are always helpful.

Just be careful not to damage the tank with excessive pressure!!! No, I don't know what pressure they are built to withstand, probably not very much.

Mesakeca wrote:
I get what you mean about the vent and that was our first suspicion also but running the sinks with the drain open or closed makes no difference. Too bad , eh? I'll post later with the 'results' of tonight's trailer fixing event. Thanks again to all of you!
Sue

Actually, that is not "Too bad." It definitely points you at the pipes just before the tank and after the shower drain. That can't be a long stretch of pipe.

If you can, run the plumbing snake down the shower's drain into the gray tank. That SHOULD break up any blockage.

Thanks Everyone for your lightening fast responses to my question. Bumpy, I'm pretty sure there is only one grey tank because there is just a very small kitchen sink and bathroom sink and shower to drain into it and they are all in a line on the same wall of the trailer. There is only one grey tank on the fill monitor. I'm pretty sure the shower drains into the grey tank. We've done stuff like add soap to the water in the sinks to make sure that what we are seeing in the shower pan is the actually coming from the sinks. Tenbear, the trailer is new to us. We just bought it privately - 'just' is the operative word here. Your thoughts about a possible drain blockage after the sinks and shower join and before it enters the tank are similar to mine. I can't figure out how to get at it to check though. A snake doesn't seem to be helping but maybe I'll give it another shot - maybe with a new and better snake. Your suggestion about back filling the tank is probably worth a try. We got it about half filled when we were back flushing - mostly because we were trying to test whether the monitor was even working -0 which it was. Then we emptied it. I'll try again tonight and fill'er right to the top to see what happens. Camp Forrest..I get what you mean about the vent and that was our first suspicion also but running the sinks with the drain open or closed makes no difference. Too bad , eh? I'll post later with the 'results' of tonight's trailer fixing event. Thanks again to all of you!
Sue

:h what bumpy said and get back with us.

It sounds like the vent pipe on the tank might be blocked. Like electricity, water takes the path of least resistance. If the vent pipe is blocked, you tank becomes a big, high pressure bubble. When water from your sink intersects the shower drain, the shower pan is easier to get to than the tank. You could test this by running your sinks with your drain open since that would prevent pressure buildup.

Is this a new RV? Take it back to the dealer if it is. If not, was it ok and suddenly something changed?

Maybe the drain from the sinks and shower join before going into the grey tank and something is blocking the combined pipe before entering the tank.

Maybe a plumber would have some kind of snake that could clear the blockage???

Maybe you could back fill the tank and push the blockage up to where you could get it out.

The alternative is to take things apart and find the blockage.

do you have more than one grey tank. does the shower drain into the black tank?
bumpy