40 psi is high, I use a pressure regulator, put it on the faucet not on the RV, if not and you have high pressure it can blow a hose. It sounds like the damage has been done and you have a water leak
(IE: busted pipe)and if so I would look in the area that is getting soaked first as far as the plugs, some people pup plugs in the shower etc to keep bugs from entering the unit through these drains, first you have to get the leak fixed then remove the plugs one at a time put water in that and check for leaks, if you find one then fix that leak, and do the rest of the plugs the same way. Good luck
