Water Out Fresh Tank - connected to City Inlet

[I M in KS]

I sanitized yesterday. Fresh tank very near empty during today's travel. Had Fresh Tank drain valve closed overnight & on todays 5hr drive . Connected to city water during setup. Water flowed as expected in camper. Opened Fresh Tank valve to ensure tank totally empty. About 30 min after setup, sitting for a beer & heard water. It was coming out Fresh tank drain (not overflow). Closed Fresh drain valve & flow stopped. Turned off city supply. Monitor shows Fresh Tank at 19 - not sure what it was before this & monitor hasn't been very reliable in the past.

Will city flow to Fresh tank if City Input check valve fails?

[Tom and Doreen]

Re-check that your valves under the curb side bed are in the proper position. There is a valve that if in the wrong position will allow city water to flow into your fresh tank.  

[Mike and Carol]

There’s a check valve with the water pump that fails occasionally.  Every now and then I get water coming out of the fresh tank overflow when connected to city water.   What works for me (until I fix it) is to turn on the water pump and let it run a bit and then it usually stops.  It’s not been a repair priority because it doesn’t  happen very often.  Mike

[I M in KS]

Thanks both for the quick reply. The valves are all in the "normal" positions. I'll ran the water pump, turned the city water back on & opened the fresh tank drain. Water drained for a short while & stopped. Water flow in the camper is normal (from city water). Monitor shows 13% in fresh, but nothing more coming out. 

Thanks again. Seems like something quirky.

[Trailblazers]

This happens to me every once in a while as well.  Check the outdoor shower to make sure both the hot and cold water are turned off.  Sometimes, especially after de-winterizing, I have found I left one of the outdoor shower valves open. Make sure they're both off and release any water pressure in the faucet, and sometimes that will fix the problem.