The flow restrictor, also called the drain restrictor, is a small part in a reverse osmosis system that controls how much water goes to drain. It is small, but it affects the membrane and your water bill.
What does the flow restrictor do?
An RO membrane makes clean water and a stream of reject water that carries the salts away. The restrictor limits the reject flow so that the membrane keeps enough pressure and works properly. New to RO? Start with how reverse osmosis works.
Why the rating matters in Oman
If the restrictor lets too much water through, the system wastes water and the membrane runs at lower pressure. If it lets too little, salts build up on the membrane faster. In areas with high dissolved salts this scale problem is common; see hard water in Oman and scale and antiscalant.
How to choose the right one
- Check the label or old restrictor for the rating (millilitres per minute).
- Match it to the membrane size and the feed pressure.
- If your water is very salty, ask a technician before changing the rating.
- If you are unsure, send us a photo of the old restrictor or of the membrane label.
When to replace it
Replace it if the drain flow looks very high or very low, or when you change the membrane. See when to replace an RO membrane for the usual signs. Read also how to match spare parts in Oman.
Where to find it
We list RO parts under accessories and fittings and RO membranes and vessels. You can also use our repair and maintenance service.
Frequently asked questions
Is the flow restrictor the same as a check valve?
No. The restrictor controls reject flow; the check valve stops water flowing back.
Can I change the restrictor myself?
It is a simple part, but a wrong rating can harm the membrane. When unsure, ask a technician.
Need help choosing? Message Clean Eco on WhatsApp or call +968 9828 1478. We are open 24 hours and serve all of Oman. The free on-site water test is available in Muscat and Seeb. Or contact us for a quote.
