[HayZee518]

each solenoid valve controls its inlet water. their outlet combines into one pipe. as Dan O said if there isn't enuf water pressure on the seat of the valve, it would tend to leak. if your inlet uses two valves (one in each cold and hot) after use shut off each valve. this will stop any future problems. if you have the washer outlet valve - (one toggle lever between two valves) it wouldn't hurt to shut this off after each use too! but if this is impractical, check the screens.