Our freshwater pump is a 40 psi Jabsco which is fine. The plumbing is all on one circuit so the pressure tank behind the generator gets pressurised by the Jabsco. Mains water is normally much cheaper than watermaker water so we switch off the Jabsco and connect the hose in the cockpit locker to the mains hose which then supplies the boat without spoiling the water in our tank. If we want drinking water we turn off the stopcock in the cockpit locker, turn on the Jabsco and run off some water in the galley first. Not sure that this would be safe in the rare marina with very high pressure mains and at any event we turn off the mains before leaving the boat.

Anne and John, Bali Hai, SM 319, Marsala, Sicily