Inline waste water flow restrictor for reverse osmosis systems — regulates drain flow to maintain correct membrane pressure, improve system efficiency, and extend membrane life. Choose the size that matches your membrane’s GPD rating.

What it does

The flow restrictor installs on the waste (drain) line of your RO system and controls how much water goes to drain versus how much gets pushed through the membrane as purified water. Getting this ratio right is essential — too little restriction and the membrane doesn’t build enough pressure to filter effectively; too much and the membrane is over-pressured, reducing its life.

Available in four flow rates (450, 500, 550, and 650 mL), each matched to a range of membrane GPD ratings. Selecting the correct restrictor for your membrane is the single most important factor in RO system performance and membrane longevity.

Which size do I need?

Not sure which GPD membrane you have? Check your membrane label or see our RO Membranes page.

Key benefits

• ✓Controls waste water flow — maintains the correct purified-to-drain ratio
• ✓Maintains membrane pressure — the membrane works at its rated efficiency
• ✓Extends membrane life — correct pressure = less stress = longer service
• ✓Four sizes covering 50–200 GPD membranes
• ✓Easy inline install on the waste/drain line
• ✓Durable, corrosion-resistant construction

Specifications

Compatibility

Often used with

Good to know before you buy

• Match the restrictor to your membrane. Using the wrong size reduces performance and can shorten membrane life. Check the GPD table above.
• Installs on the waste (drain) line only — not the purified water line. The restrictor controls how much water goes to drain.
• Replace when you replace the membrane — flow restrictors can clog or wear over time, so swapping both together keeps performance consistent.
• If you’re not sure which GPD membrane you have, check the label on your current membrane or look up your system model.
• A restrictor that’s too small (under-restricts) lets too much water drain and the membrane can’t build pressure. One that’s too large (over-restricts) forces too much pressure and stresses the membrane. Match it.