I, too, am considering an outdoor shower to rinse / wash off after working in the yard; I get really nasty trying to keep the place tidy. I spoke to a couple of my plumber friends about the best way to get hot water. They said the easiest was the electric instant style hot water heater but theres a catch. They also said it typically uses a 40 amp ( double pole??) style breaker and your home must have both enough unallocated electricity and space in the breaker box. The house has a 200 amp panel, but is total electric and is probably close on spare capacity. When I finally get around to being serious about the shower, Ill call an electrician in to make sure it will work. Just thought Id throw that out there for folks thinking about it.
Ive been thinking out an outdoor shower too. Id have a pretty easy job for supply water. The water heater is just on the other side of the wall where I want to put the shower. Im just trying to figure out the drain. Do I let it drain to a gravel pack, or plumb it up to the septic?