Over flow on fresh water holding tank

[rdream]

2012 26 DSRL White Hawk
We are camping at a site with City water. We left the campground today for a site seeing trip and I left the City water supply on to the TT. I have a pressure valve on the campsite water supply and a filter before water enters the TT. Upon coming back we entered the trailer and water started running out of a tube by the right rear side under the trailer on to the ground. It had not been running when we first got back, only after walking into the TT. I turned off the city water supply and the water after a minute stopped. I checked the sensor panel and it showed the holding tank full that normally has 10 gallons in it for on the road stops for the toilet and washing hands. Can anyone advise how the valve opened to back fill the holding tank? Why did it wait until we entered the trailer to begin to dump water on the ground? Or am I missing something and I have another problem?

[tnchuck100]

There is a check valve in the water pump that is supposed to prevent city water from flowing to the fresh water holding tank. There could be a particle of sediment preventing the valve from seating correctly. Or the valve could have just failed.

You might try removing the city water and allow the pump to run water from the fresh water tank in an attempt to flush any sediment from the valve. If that does not help you can purchase a check valve that you can connect to the pump. That would be considerably cheaper than replacing the pump.

If you don't already, always use a filter when filling the fresh water tank. It will reduce the chance of sediment creating problems with the valves in the camper.

Hope this helps.