Check valves on water inlets

[Osage]

Hey all,

So found a crack in the inlet valve of my fresh water inlet. Going to replace it and most feature a "check valve" that I'm sure the original did not have.
Does it matter?
Do I want to have a check valve?

Thanks

[5picker]

All R/V city water inlet ports have check valves built into them.

If they didn't, when you were not on city water and using the pump, the water pressure from the on-board pump would squirt water out the city water inlet. The check valve is located behind a cone shaped screen. You may have just never seen it.

[Osage]

OK, thanks. Understand the purpose. If I replace the cracked fresh water inlet that currently has no check valve, with one that does. Should not make any material difference, correct?
My fresh water inlet only connects to the fresh water storage tank. City water to all the plumbing fixtures.

[5picker]

OK, a misunderstanding of terminology.
Fresh water tank fill inlet vs city water inlet.

If your fresh tank has a garden hose threaded inlet to fill the fresh tank instead of the cap style gravity feed, then no, it does not need a check valve but having one will not hurt anything.

You can easily pull the check valve out of the inlet with a pair of needle nose pliers.

[Comanchecreek]

I guess we're misunderstanding your problem. Is your problem a crack in your fill for your fresh water tank? No check valve there that I've ever seen. IF you are talking about your city water hookup, then you need a check valve that prevents water from escaping when you pressurize your water system by your water pump. If you are just hooked up to a water hookup, it's not as important except you'll get a bath every time you start to disconnect the hose as the system will hold water pressure until you unscrew the hose.
After rereading your reply, be very careful about putting a screw on hose fitting for your fresh tank fill. You will pressurize the water tank when it fills, and there is no pressure relief on the tank. It can crack your tank, and/or blow fittings apart attached to the tank, and fill. When I fill I run the hose just until the water back flows out of the fill. No pressure built up.

[5picker]

Fresh water tanks have overflows and vents.

Not all units have gravity fills.


Many units come from the factory with a threaded, garden hose fitting for filling the fresh tank. I believe this is what the OP has and has asked about.

While you can force more water in under pressure than what may come out the overflow or vent, they are not closed systems but your advice of being careful is valid as we have seen reports of tanks bulging when filling and breaking/bending supports and lifting/buckling floors from blocked vents and overflows when filling too fast.

[Osage]

Thanks guys, all good replies.
Yes, my fresh water fill uses a garden hose screw fitting. The fill tank has two vents to prevent over pressure and over-filling. But I watch it anyway while filling.
I suspected that the check valve would not hurt, and also guessed that it would be removable without much difficulty if it did.
So thanks again.