For every gallon used, the system will reject 2-4 gallons of waste water depending on the quality, temperature, and pressure among other factors. This is a standard norm of all reverse osmosis products regardless of the brand or company. This can be reduced by adding a dual membrane, ERP Pump, or booster pump. 2. Min PSI for the system to work is 50 PSI. 3. Do not keep outside in freezing temperature.