Water Filling Fresh Water Tank From Campground Water Connection???

[plh869]

We used our camper this weekend for the first time since last season. We never use the fresh water tank. We always connect to city or campground water supply. We realized we had a lot of water in our fresh water tank which we made sure was completely drained, dry, and empty when we winterized it. The only thing we can figure is that somehow water is back flowing into our fresh water tank from somewhere probably the city water line. We’ve never had this issue! The fresh water tank was empty all season last year. Any ideas or suggestions as to what could be causing this! The freshwater tank was almost full of water just from this weekend and we were connected to campground water!!!! It took forever to empty it from the drain. Thanks so much for any ideas!!!

[Fluffywhitedogs]

It’s a check valve and there’s an easy way to fix it that usually works. The search function sucks on mobile but try the search “check valve” or I’m sure someone will post it. It comes up quite regularly...

[CincyGus]

I would hook up to a water hose at home, open up the compartment where the water pump is, turn on the water at the house to pressurize the system and then be checking the water lines that run from the fresh water tank out.

My guess is you have a valve bad somewhere in the system that is allowing your issue. There should be no way for it to flow backwards and there are valves in the system to prevent, obviously one of which has failed.

[ependydad]

Here you go:
Problem! Freshwater Tank Unexpectedly Filling When on City Water | Learn To RV

The check-valve in the water pump is stuck "open". Typically just alternating between city water and the water pump a couple of times will reset it. In the meantime, run off of your freshwater tank to use up the water.

[Hi Rider]

I've had the same problem 2 or 3 times. It is the check valve on the pump. The check valve sticks open allowing the city water input to fill the lines and then pour into your fresh water tank. My solution was to turn a kitchen or bathroom tap on and off a few times and that fixed the problem.

[Swampy]

Originally Posted by plh869

We used our camper this weekend for the first time since last season. We never use the fresh water tank. We always connect to city or campground water supply. We realized we had a lot of water in our fresh water tank which we made sure was completely drained, dry, and empty when we winterized it. The only thing we can figure is that somehow water is back flowing into our fresh water tank from somewhere probably the city water line. We’ve never had this issue! The fresh water tank was empty all season last year. Any ideas or suggestions as to what could be causing this! The freshwater tank was almost full of water just from this weekend and we were connected to campground water!!!! It took forever to empty it from the drain. Thanks so much for any ideas!!!

plh869,
Sounds like a stuck check valve on the water pump ... probably some construction debris in the valve seat. Normal simple fix is to turn the pump on and let it pressurize the system (where it will automatically shut off and hold the lines pressurized). Then give it about 15 minutes to see if the debris is out of the valve. If the pump starts up on it's own without anyone opening a faucet, let it run again until shutoff. Sometimes you need to repeat until it can clear whatever is in the valve causing it to leak. If after several cycles, it still leaks, then you may need to locate the pump and carefully remove the valve mechanism and hose connections from the top of the pump. Then manually clean and reassemble.

I hope this helps .............. Swampy

[Easymoney]

or you had too much water pressure. pump check valve will only hold to about 50 lbs, some campgrounds have as much as 300 lbs pressure depending on where you are connected in the line.

[bikendan]

I see this happening a lot, to those that rarely use the FW tank.
We have dry camped mostly, for 30 years and have never had a stuck check valve in any of our RVs water pumps.
It's my opinion that you should exercise the pump, every once and awhile. Even if you always have city water hookups.

[Life Without Whine]

We did all these things & have not had an issue lately but never want that tank to overfill again so when we get parked we take the plug out of our fresh water tank so it cannot back up & flow into the storage compartment again. We shut off water when we leave the site (& figure if we forget someone will happen by & turn it off for us if draining underneath). Happy camping.....

[beechjet16mf]

The check valve in our water pump sticks a lot, so I bought a Camco brass one that installs on the intake side of the pump and that stopped the problem.