for those interested in electric water heaters
I live full-time in an airstream and, like everyone else who has gone vintage, had bad leaks from the old water heater (Bowen 9.9 gallon model) back in November. I didn't have enough money to replace it with the same model so I got creative. If you're going to be in areas where you can be plugged in, and you are looking for just enough water for a shower (including hair conditioner ha ha), I highly recommend looking into the Ariston 4.0 gal point-of-use water heater. They're about $180 but I got mine at Home Depot for $130 and did the job myself (with a friend and no prior plumbing experience, but a little research) for under $200.
At first I was skeptical, but I was desperate since the leak was awful and I needed to bathe! The Ariston plugs in to the outlet on the wall (with a little help from a circuit breaker thing) and turns on by a switch. It has a red light that turns off once it's hot. If you set it as hot as it will go, which you should, the water will be hot enough to burn you for a couple minutes (which I don't recommend). Because it's so hot, the cold water dilutes it just long enough for a shower. I usually get warm, stop & shampoo etc, rinse & stop, condition, rinse and have a little bit of warm (real warm) water left. I'm really proud of my little gadget, and it has a 6 year warranty! (Most water heaters will give you about a year if you're lucky).
Besides the obvious downfall of having a quick shower, another issue is the space in the outside shell where the old water heater was. I had a piece of plywood cut to fit the opening and there are drill holes around the perimeter of where the w.h. used to be that one can drill into. Of course then you have a chunk of plywood on the side; I don't care for now, its sealed with duct tape and I stayed within my measly budget.