After I re-read this. Are you talking about actually unscrewing the board under the mattress ?
Wouldn't the shower be effected if something wasn't working right under there ?
We both used the shower and there was no problem.
I crawled under the coach this afternoon and I could not see anything leaking or wet looking.
I swore I heard dripping in the wall in the middle of the night but as I mentioned there was nothing wet outside on the ground and Vince just thought I was imagining the noise
Carol & Vince
My first thought is that the tank drain is open. if you have the pump turned on when travelling possibly the outside shower is open. Water will run out the overflow tube when the tank is full as the coach rocks.There are also drains for the shower that may be open. You might want to check under the bedboard to check the tank and the hoses.