Questions & Answers for: Keystone Alpine 3720FB valve tank

...is usually a drain valve for each tank could be under trailer in middle some where Here is the solution if your still having the problem. Camco 39062 Dual Flush Pro Holding Tank Rinser with Gate ...

flow through the pump backwards and into your fresh water tank. Typically this requires ether replacing the pump or installing a secondary check valve between the fresh water tank and the pump suction