Fresh water tank

[Susancason]

My RV is 8 months old. The fresh water tank seems to fill on its own. I'm hooked up to city water and am not using the pump. There should only be a small amount of water in there. Why is this happening?

[Openroadorer99]

There is a check valve that if working, will not let that happen.
You could have a bad or stuck check valve or what happened to me.
I had that problem after not having a water psi thing on the hose at one place, and it caused problems with water back filling my fresh tank and overflowing it, . I ended up taking the pump apart a few times, to finally get it to stop, but never trusted it, so cut in a shut off so it will never happen again. When on city water, i shut valve off, when on tank, turn valve on.
Try shutting off the city water and running on the pump, the pump should hold pressure, if it cycles on its own, the pump may have a problem.

[bikendan]

Originally Posted by Susancason

My RV is 8 months old. The fresh water tank seems to fill on its own. I'm hooked up to city water and am not using the pump. There should only be a small amount of water in there. Why is this happening?

There are literally thousands of threads on this topic, as it is a very common problem.
A quick search in the Plumbing/Water Systems sub-forum, will get you weeks of reading.

[Mike_n_Kelli]

Originally Posted by Susancason

My RV is 8 months old. The fresh water tank seems to fill on its own. I'm hooked up to city water and am not using the pump. There should only be a small amount of water in there. Why is this happening?

You might want to check the valve in the shower. If you are using the bypass switch when you are showering it re-directs the water into the main water tank. Its done in a way to help conserve water. We have the Rockwood 2608BS - and had the same problem. My wife that water miser valve was the way to shut water off instead of at the shower head. Hope this helps

[Rhumblefish]

1. stuck check valve. <- super duper, extra, ultra common, most likely this
2. showermiser improperly set. <- probably not this, doesn't hurt to check
3. Use the site search. <- we get this question ALL the time.


4. Shut off city water, run pump. Turn off pump, run city water. Repeat. This is "exercising" the check valve.