I did mine mainly for boondocking. Tee into hot water line at galley wit a 1/4" line to the inlet side of the water pump. In that line put a 12v selanoid valve. Control that valve with a remote control on/off switch with 2 remotes, one in the bathroom, one in the galley. Push the button and circulate water from the water heater, back to the tank/pump inlet, count to 20 and water is hot. It can be used on city supply but need to make sure you don't forget that it's on, it will over fill the water tank.
