Water Pumps Out of the City Water Inlet

Greetings. I keep my 29-foot Dutchmen Class C parked under my pole barn.  It's plugged in for power but nothing else is hooked up. I've just noticed that when I turn on the water pump, it pumps gallons of fresh water out through the park water hose inlet. It's emptying my fresh water tank. When I turn the pump off, it stops. The pump is only a few years old. I would appreciate any guidance. Thanks! Jim Mac

Jim, all RVs have at least two backflow preventers (check valves) in the fresh water plumbing system. Some RVs have three and some actually have four backflow preventers. Every RV has one at the city water inlet which allows water to flow from the campground into the RV. The backflow preventer at the city water inlet has obviously failed in the open position. It will have to be replaced, or at least a new one installed right behind the existing one. Since it failed in the open position, it's not really necessary to remove it (though it's advisable if you can). A new backflow preventer can simply be installed just inboard (downstream) of the old one. That will prohibit water pushed by the onboard pump to be forced out the city water inlet. Actually, it's not a difficult task for the average handyman to accomplish in a few minutes....once you gain access to the rear of the existing check valve.

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