I have a reverse osmosis system (Watts fmr04-man) that started constantly draining. It's been installed for 5 years. 2 years ago, it did this and I replaced the filters and membrane, which resolved the issue. However, that gets expensive and I'd like to do more troubleshooting.

When I shut off the pressure tank valve, the draining stops within 5 seconds. I believe this means the ASO is working and so is the check valve. When I turn it back on, the draining resumes within a couple of minutes.

What are my next steps?

  • what is the tank pressure ?
    – Traveler
    Commented May 10, 2023 at 8:14

2 Answers 2


If your water supply to the RO unit is via a saddle valve, replace the saddle valve with something that provides a higher flow rate


Turns out, was the membrane. Replaced it, everything is fine.

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