[rdunk]

Isn't the "check valve" being discussed actually a "backflow preventer" valve? These valves are required (probably mandated by health restrictions) to keep "trailer water" from flowing back into the public water lines. When mine went out, that is what the dealer tech person called it. They are made in brass or some type of plastic. The tech said the brass seem to last longer. When he replaced mine, he also left a spare, which I haven't needed yet.

I think there is another "backflow preventer" on the incoming water line in our MS.

I have noticed that some of the RV parks are installing a "backflow preventer" on their water faucets. Yes, these valves do reduce the incoming water pressure by the amount of water force that is required to open the valve to allow the fresh water to go through.

Our water filters also reduce our water pressure. The greater the filtration, the more the pressure is reduced.

FWIW