I carefully added some water to the holding tank of my Casita
to see what condition the system is in this afternoon. After putting in a few gallons, water started running out of a small fitting on the side of the trailer. It's a round, white plastic device held on with 2 screws and which has a plain hole in the center, maybe 1/4" diameter. I dug around under the bench where the ater tank is and found that this is connected to a fitting on the bottom of the water tank. It's apparently a drain, but how do you shut it off? Is there supposed to be a plug of some sort in the hole? There was not any kind of manual valve between the tank and the side of the trailer and there's nothing on the outside.
There is a vent or overflow tube connected to the side of the tank at the top, which runs down through a hole in the floor. There is also a 3-way valve on the main outlet of the tank with a length of hose coiled up and connected to it - for drawing antifreeze into the system, I would suspect.
I did run the water pump some, enough to find a couple of leaks
and to get some truly foul-looking, rusty pink antifreeze out of the sink faucet.
It's going to need a thorough flushing and bleaching before I'd even want to take a shower with it.
I think I'd probably want to carry my drinking and cooking water in jugs, anyway.
The cubby where the water tank is located is pretty musty - there are 4 strips of wood screwed to the floor to help stabilize the tank, and a couple of them are pretty rotten-looking. I think things had leaked at one point back there. I think I'm going to replace some of if not all of the tubing - it's pretty scummy.