I've always had foot pumps for the galley
… but a pressure system for the heads' handbasins and, of course, the shower
and hot water system. I can't imagine the contortions of trying to operate a foot switch while showering in a seaway.
I find the concept
of foot switches rather strange as the pressure systems I've had have all worked automatically when a faucet opened. In other words … the water was always under pressure and the pump actuates when an open faucet drops the pressure below a threshold. If you are worried about possible leaks
and wastage … the pump is a single
switch. This also has the benefit of the least amount of wiring
In regard to fresh water consumption
… I've always used sea water for most things, other than food
prep, drinking and final rinse off of anything destined for mouths. A good salt water
soap and shampoo does a fine job for salt water
showering. A final rinse off under the fresh water shower stops the salty feeling.