Why Is My RO System Draining Constantly?

A healthy reverse osmosis system should only drain water during active filtration. Once your storage tank reaches capacity, the system should shut off completely. If you hear water continuously running to drain, even when no one is using filtered water, something is preventing your system from building pressure and cycling off properly.

Why This Matters

Constant draining is more than just an annoyance. It wastes significant amounts of water, increases your utility bills, and puts unnecessary wear on your membrane and other components. Left unaddressed, what starts as a minor valve issue can lead to premature membrane failure and costly repairs.

Common Causes

• Failed check valve: The check valve prevents backflow from the storage tank. When it fails, water flows backward through the membrane, keeping the system in a perpetual filtration cycle.
• Auto-shutoff valve malfunction: This valve senses tank pressure and shuts off incoming water when the tank is full. If it sticks open or fails to read pressure correctly, the system never receives the signal to stop.
• Flow restrictor problems: The flow restrictor maintains proper pressure on the membrane. If it becomes clogged or damaged, the system cannot build adequate pressure to trigger the shutoff mechanism.
• Membrane housing issues: Loose fittings, cracked housing, or an improperly seated membrane can cause pressure leaks that prevent the system from reaching shutoff pressure.

Troubleshooting Steps

Before replacing any parts, try these diagnostic steps:

• Check your tank pressure: Disconnect the tank and use a low-pressure gauge on the air valve. Empty tanks should read 7-11 PSI. Incorrect pressure can prevent proper shutoff.
• Inspect the check valve: Located after the membrane housing, this small valve should allow water to flow in only one direction. Blow through it gently, air should pass one way but not the other.
• Test the auto-shutoff valve: Close the tank valve and let the system run for a few minutes. If it shuts off, your tank or check valve is likely the issue. If it keeps running, the auto-shutoff valve may need replacement.
• Examine tubing connections: Look for loose fittings, kinked tubing, or visible leaks around the membrane housing that could cause pressure loss.

When to Contact Support

If you have worked through these steps and the problem persists, or if you are unsure about performing any of these checks, our technical support team is here to help. We can walk you through additional diagnostics or recommend the appropriate replacement parts for your specific system. Reach out to Crystal Quest support with your system model number for personalized assistance.