HELP! Fresh water tank filling when valve set to “City”

Why stay hooked to city water? Safer to fill your tank and use water pump.

We have the same problem with our 2017 Mobile Suites. We just watch the tank level and turn off the water if we see an increase and run the pump. We don't like to travel with more than 15 gallons in the fresh tank. Just enough to flush the toliet while traveling.

It might be the check valve by the water pump. Try using the pump for awhile it might undo itself. If I remember correctly it was an inexpensive plastic valve that was easy to change.


youtube, will show you how to access it and clean it.
if that does not take care of the problem then the selector you mentioned might be bad.

“We don't like to travel with more than 15 gallons in the fresh tank.”

Then don’t stop at many beautiful Southwestern CGs cuzz you won’t find any water.

This has happened to us twice now. The valves in our pump get old or dry out and the water backflows through the pump into the fresh water tank. I've had to rebuild our pump each time. It's a Shurflo 2088 and you can get parts on Amazon.

I have the same problem and it is the check valve in the pump. For a bandaid fix, a dealer put a cutoff valve before the fresh water tank (under the bed in my case) to keep the city water from filling the tank. I do need to replace the water pump or rebuild it, in my case, since I have replaced one before in another unit, I will just put a new pump in. My biggest issue, is when I use the pump, I have to turn it off each time as it keeps pulsating even if no faucets are open. Guess it is backflowing into the tank.

LadyRver wrote:
I do need to replace the water pump or rebuild it, in my case, since I have replaced one before in another unit, I will just put a new pump in.

Same here , I started carrying a spare pump. It's so simple to do, I just swap it out then rebuild the bad one at my leisure.

While at a site, it's a good idea to have water in the fresh tank to use in case the campground has a city water leak and they need to shut down there system for a period of time. I just unload it before I travel again. Like others I only run with 10 or 15 gallons.

Is it possible you're connected to the wrong inlet? The black star shaped thing at the lower left of the pic looks like it could be your city inlet. Undo the hose, connect to that, leave the valve on 'city' and see what happens. Be sure to use a pressure reducer.
The inlet that you're connected to may only be for filling the tank. Seems like it would be more clear if that valve simply said 'open'(city) and 'closed'(tank full).

I think you’re hooked to the wrong inlet. The older trailers have a gravity fed inlet. You just kinda prop the hose up and let it run until it overflows. It was not threaded.
Try moving the hose like pmallone suggested.

it's a bad check valve in the water pump
check the brand and model number.
go on ebay and get a rebuild kit for about $10.
i think 4 screws and it all comes apart.
check out youtube. mine's a sureflo

good luck
larry