Tanais' activities (nice job on his part) remind me to finish up some tasks I intended to do long ago, mainly to have a working water collection system.
The metal roof and gutters have already been plumbed and fitted to a point sink complete with drain pipe that ends at an energy dissipator. Presently the water collected from the roof splashes onto the rocks and heads downward. All I need do is run a length of pipe from there to the two 5000 gallon collection tanks, probably through a coarse filter to keep the leaves and other detritus out. The harder part is preparing a slab for the pressure tank and recirculation pump and UV cleansing system. I have conduit runniing from the house to the dissipators, but I will have to run conduit all the wy tothe tanks too.
I will most likely buy an evacuated tube system because I want a *lot* of hot water, even in the winter. The rest of the system, however, is mine to design. The basic approach will be to have a 300-500 gallon super insulated water tank underneath the deck by the hot tub. The evac-tube system will be glycerin & water running through a heat exchanger with a diverter valve system. One run goes to the existing hot water tank to keep it heated. This keeps the propane off. The other run goes to that massive tank. That tank supplies hot water to the nearby outdoor showers, and it heats the hot tub at night. This should completely eliminate eletrical heating.