My first step is the plumbing test. I've learned my lesson with plumbing for my home, and if memory serves me right, I know that I'll want to make sure the plumbing works all the way through before sealing up the wall of a new construction project.
I had a few burning questions that were in dire need of answering, the first being, "Is it possible to use bathroom hardware, commonly found at a home improvement store, for an RV?" After searching the net for bathroom and kitchen fixtures, I began to grasp the dismal selection of interesting options offered by retailers of RV accessories. Basically, the stuff is just plain junky and ugly looking. The decor variety is virtually at zero, and the options for a variety of features stand exactly at zero.
I knew that there must be more in store and I couldn't see why a Moen fixture wouldn't work with a 1/2" plumbing system in an RV the same way it works in a building. So, here's the fixture I purchased. It's a Moen single handle 3 port valve for use in a "shower only" bathroom system.
Of course, once I got everything tightened up and found the proper way to prevent plastic tubing from spewing water in every direction from every junction, my Moen brass valve stopped the flow of water beautifully. A word of advice: Buy the connectors used for "PEX" tubing. Snapping the system together requires no tools or teflon tape. If Fisher-Price made "My First Plumbing System" for toddlers, this would be it.
Next in line was the question of heating the water. Upon looking at the standard issue two-handled RV faucet, I surmised that this common style of valve is actually inefficient for a system that has a limited water supply. It occurred to me that one would have to fiddle with both handles to properly adjust the temperature while sending a huge amount of precious water swiftly down the drain. And, my tank will probably hold no more than 50 gallons. At 2.8 gallons of pumping volume, my water capacity won't last for very long if I wish to shower on a daily basis in my portable home. I figured that with a single-handled valve, I could easily remember the setting for a comfortable hot and cold water mixture.
My choice for water heaters was made after researching a few of the outdoor camping showers offered on line. The Eccotemp on-demand camping shower looked small and simple to use, so I went for it. The packaging says "for outdoor use only" yet, I've never met a water heater anywhere that was designed for indoor use. Obviously, proper mounting in a dedicated compartment and adequate ventilation is in order, something I've already designed into my van layout. I hooked the heater to a propane tank and the water line "in" and "out" spigots, and turned it on. It operates on -- get this -- two "D" batteries. Can you imagine that? Talk about low energy use.
Of course, I'll have to transfer the on/off switch to a better location inside the cabin, but aside from that hurdle, the system worked beyond expectations. Upon turning on the faucet handle, the pressure switch from the pump activates, sending water through the heater. The heater's pressure switch activates the burner, thereby sending instantly (and I mean instantly) heated water right to the faucet. I even added a realistic length of hose I think will be necessary for carrying hot water from the heater's location to the shower faucet.