Fresh water tank filling from city water connection?

[TeamRAB]

Hey guys and gals,

A couple of weeks ago I posted a question about drainage from a tube at the bottom of my trailer. It was concluded that it was an overflow drain for the fresh water tank. I drained the tank and everything has been fine.

Cut to this morning. I step outside to drain the grey tank before I take my shower, and see that the overflow valve has been dripping water.

I check the sensors and it tells me that the fresh water tank is full.

Is there any way that the fresh water tank could be filling up from my city water connection? Possibly a valve I missed closing when I sanitized the tank
A couple months ago?

Thanks for your help!

[JaycoMLOK]

A bad check valve in the fresh water pump.

[TeamRAB]

Originally Posted by JaycoMLOK

A bad check valve in the fresh water pump.

So is that something that I could fix myself? Or is the solution to have the pump replaced?

[Screwby]

Originally Posted by TeamRAB

So is that something that I could fix myself? Or is the solution to have the pump replaced?

If it is a brand new camper or hasn’t been used in awhile it might possibly fix itself. Sometimes the check valve gets dry or sticky after sitting and just needs used a little bit to “exercise” it back into good shape. Use your water pump for a bit and it’s quite possible it will be ok. Fairly common problem. Worst case it’s a bad pump and it’s easy to replace. A couple power wires and screw on fittings.

[JaycoMLOK]

Yes but sometimes by turning off your city water and turn your pump on and open a faucet so the pump will run. Cycle the pump a few time sometimes that will clear any small debris that may have stuck in the valve holding it open.

[distracto]

I picked up this part for my pump as i had the same problem in my old trailer. Was pretty annoying as I always had to drain the tank before leaving if at a full service site.

https://www.amazon.ca/gp/product/B00UYWVIU0/

[TeamRAB]

UPDATE!

Just got to the new site and attempted to hook up. After turning on the water, this happened.

Two parts to the same problem, or new problem all together?

https://pasteboard.co/JpzCe3X.jpg

[norty1]

When it rains it pours. Hopefully the check valve will hold until you can get a new connector.

[TeamRAB]

Yeah, I’ll replace it on Monday when we roll into a town. Out in west nowhere North Dakota right now.

[TeamRAB]

So, I replaced the city water input flange. But the fresh water tank is still filling. Is there something I missed?

[Scott_Trailer_Newbe]

It’s not the flange, its the little cheap check valve under the pressure switch. Had the exact same problem. Tore apart the pump to gain access to the check valve [under the pressure switch] cleaned it with a rag and put it back together. Hooked up city water and waited, no overflowing of the fresh water tank. its a common problem with these little cheap 12V water pumps.

[Cavie]

Originally Posted by TeamRAB

So is that something that I could fix myself? Or is the solution to have the pump replaced?

You can get rebuild kits on And do it yourself. Easy job. You can also install a check valve after the pump.