On demand water heater and boondocking

Many people keep gallon jugs in the kitchen and shower to catch the cold water, then use it to flush the toilet, etc.

Unless you are always in a full hook up site {and the OP is not}, tankless water heaters are water waisting disasters. :S They will drain your freshwater and fill your grey tanks with equal speed. The venerable AC/LP 6 gallon water heaters found on most RV's have been doing their job well for decades.

My bride and I can take two quick showers and never run out of very hot water, even if I used it all the LP side will reheat the entire tank in about 10 minutes. We have steaming hot water at the kitchen sink in about 15 seconds and the shower/bathroom sink takes less than a minute. A full 40 gallon fresh tank lasts us nearly a week. In the warmer months we like to use the outside shower to save capacity in our grey tank and yes, these old folks always wear our swim suits {you're welcome}. :B

Assuming you have the room for a conventional AC/LP 6 gallon water heater budget about $500 for the unit {the internet is your friend} and another $200 for the install. If it comes in for less hooray. I "could" do that install myself but it can be a serious PITA best left to a qualified RV tech {my Indie charges $90 an hour most dealers are around $130+}.

As always... Opinions and YMMV

:C