R/O Spare Parts

The most frequently replaced parts are the ASO (automatic shut-off) valve, which controls when the tank fills and stops, the check valve, which prevents backflow from the tank, and the flow restrictor, which controls the reject-to-permeate ratio. Storage tank bladders and feed water solenoid valves are also common service items.

A failed ASO valve typically causes the system to run continuously without shutting off when the tank is full, or to stop producing water entirely. You can test it by checking whether water still drains to the waste line after the tank is pressurized. A stuck-open valve wastes significant water.

The flow restrictor limits drain water flow to maintain the back pressure the RO membrane needs for efficient ion rejection. A clogged restrictor reduces drain flow too much, which lowers TDS rejection. A missing or failed restrictor allows too much drain flow, reducing membrane pressure and water production.

A failed bladder typically results in the tank feeling heavy (filled with water) but delivering only a short burst of water before pressure drops. The tank will also fail to hold the 7 to 8 PSI air charge when empty. Bladder replacement restores normal tank function at a fraction of replacement cost.

Many components such as 1/4-inch fittings, standard ASO valves, check valves, and flow restrictors follow industry-standard sizing and thread patterns used across most residential RO systems. Confirm the flow restrictor GPD rating and valve port sizes match your existing system before ordering.