De-winterizing gone wrong

thanks for the tips, the water line in the wall was holded by a staple. had gone unnoticed because I alway used a inline pressure reducer.   did a splice using pec splice and crimps.  also found the water tank drain plug, it was in the furnace hatch.  so all is good.  thanks

You have a couple problems, not directly related to each other.

The cap for the FW tank is 1/2 NPT threads. Any hardware store will have one, or any RV parts store. Buy a spare.

You can "dewinterize" with city water, but most people ALSO sanitize the system at the same time, so they use the holding tank.

Using a pressure regulator is a good idea, though generally not needed at home, most modern homes have one on the system already.

My "guess" is the water lines up to the shower controls are leaking, the only way to find it is to keep looking..

The low point drains are just that, "drains". They need to be plugged when the water system is in use.

Just bought a RPod 171 late last summer, had a dealer winterize it as it was in their shop for warranty work on the stereo.  So just getting ready to do some camping this summer and proceeded to dewinterize it.  I noticed the fresh water tank is missing its drain plug.  So I hooked up the hose to the side of the unit and turned it on thinking I could flush the system (pressure water).  I soon noticed water (pink) coming out from under the bathroom.