The back flow valves are notorious for leaking whilst in use. When I am flushing my tank I place water absorbing towels under the valve just in case and I am always running back and forth between my control panel, the bathroom sink area(where my back flow valve is) and outside the trailer, always looking and listening to make sure everything is going well..
TT: 2015 Jayco Jayflight 26BH Elite
TV: 2014 Ram 1500 Sport, 5.7 HEMI 3.21, Firestone 1000# air suspension. WD hitch w/800# bars
SOLD: 2012 Jayco J-series 1007