It could possibly happen, but the black tank is not pressured and the inlet hose inclines from underneath the unit to part ways up the side. The valve mfg states that the valve will vent water at any time. There are rubber flappers inside, and they will stick, causing the water to run out the top. They have a redesigned valve, that mounts on out side of unit, and sent me one no charge when mine sealed shut. and flooded my t/t. Had a long battle with Jayco and valve mfg. last year over this problem.