18-Gallons Per Day Production Rated Maximum Output Capacity @ 50 PSI Input Feed Water Pressure. GE/Desal Brand. PLEASE NOTE- The "Gallons Per Day Production Rated Maximum Output Capacity" on these TFC-Dry Membranes may be less than the Listed Rating since the Membrane Output is affected by the input Feed Water PSI, Temperature, & TDS Levels. If your system has less than 40 PSI Input Feed Water Pressure, you should add a Booster Pump to your system or the Membrane will not clean up your water as rated.