How to clean and sanitize Reverse Osmosis system

sanitize reverse osmosis system

Reverse Osmosis system purifies water by filtering through all the sediment, bacteria, pollutants and nutrients. In fact, a decent RO system purifies water to such a level that it even becomes too pure resulting in empty taste. So it’s common practice to reintroduce some useful and healthy minerals by remineralizing the water before drinking.

While the RO process discards most of the removed matter from the water, a part of what filters through stays in the system itself. That’s why a regular filter change is necessity and a thorough system clean-up is needed.

Don’t get repelled if at first, it looks complicated. If you’ve managed to install your own RO system, you’ll be fine with cleaning it up and the benefits are definitely worth it.


You will need Teflon tape and filter wrench that was included. Optionally, you can get some silicone to make a better seal with the O-rings. If you’re planning to clean RO membrane as well, you will need plumbing pliers.

It’s a good idea to pick up some special solution made for RO systems cleaning that most manufacturers offer. Although you can use a quarter cup (about 3 tablespoons) of simple, unscented household bleach, hydrogen peroxide or chlorine. Basically, any NSF approved sanitizer will work.

Pro tip. You should only work in a clean environment. If needed, consider taking a bucket of water with the same solution and washing the filter casings and the tank before disassembling.

Step-by-step guide: how to sanitize RO system

touching reverse osmosis system

You’ll have to go through 15-step process to fully sanitize your Reverse Osmosis system:

  1. Start by washing your hands clean.

    You can also wear disposable gloves.

  2. Turn off the water supply to the unit and disconnect anything you have hooked up to your RO system such as ice makers.

  3. Open the water tap and allow for the system to empty itself fully and depressurize.

    Simply wait until the flow stops.

  4. Unplug all the tubing and take the unit out somewhere where it’s clean, you don’t need to work while squatting under the counter

  5. Remove all the pre-filters as well as the RO membrane from their housings.

    – If you’re not doing filter change, put them either in damp and clean bags or a bucket full of water.
    – If you will be replacing filters with new ones, discard the old ones.
    – If you will be replacing the final polishing filter – keep it plugged in. Otherwise, arrange the tubing in a way to bypass it while flushing (more on that later).
    – There’s no need to wash the remineralization compartment if your system has one. Arrange the tubing to bypass it.

  6. Add the sanitizing solution into the housing of the first stage sediment filter and screw all the empty housings back on.

    There should be no filters installed, except for that post-filter that is going to be replaced. Tighten them to avoid leaks.

  7. Turn on the water supply and after a minute or two open the RO faucet to check if the water is coming through, then close it again.

  8. Let the storage tank fill and allow the cleaning solution to stay in the system from 30 minutes and up to a couple of hours.

  9. Now it’s time to flush the entire system. Open the tap and let the whole water come out.

    Afterward, let the tank refill two more times and repeat the flushing. Then check if all sanitizer scent and visual clues have vanished. If not, repeat the flushing once more.

  10. After you’re sure that the system is clean it’s time to install the filters. Your old ones or new ones, the procedure will be the same. Turn off the water supply and depressurize the system by letting the whole water out.

  11. Unscrew all the housings and start replacing filters in order from first to the last.

    Make sure that the rubber O-rings are in the right place. At this point, you can apply some extra silicone around them.

  12. Put all the tubing back in order, but do not open the valves to the icemaker or fridge just yet.

  13. Turn the water supply back on and open the RO faucet, let the water run for a couple of minutes while checking for leaks in the system above.

    If you’ve replaced the polishing filter, then some black water and oxygen might be coming out. Don’t worry, this is normal and will pass.

  14. Close the faucet to let the tank fill.

    If you’ve installed new filters, it’s usually recommended to discard one to two full tanks of water before use.
    Some specific manufacturers require to purge reverse osmosis for 24 hours by letting the water go through it with an open RO tap. Do refer to your manufacturer’s instructions for actual recommendations.

  15. Finally, you can reconnect your ice maker or refrigerator and enjoy clean water.

How to clean Reverse Osmosis membrane

reverse osmosis membrane

While you wait for the solution to do its job you can also clean the reverse osmosis membrane. Usually, a telltale sight that you should clean or replace a RO membrane is increased pressure from the tap.

  • The process itself is dependable on the chemical solution that you need to buy beforehand and the recommendations of a manufacturer.
  • Take into account dosage, temperature, pH-values and contact time guidelines.
  • The process will involve soaking the membrane in different chemical solutions in steps and rinsing in between.

After you’ve finished, install the membrane back in the housing at the same time with filters and proceed with system flushing procedures.

How to clean a Reverse Osmosis Tank

reverse osmosis tank

The tank stays connected to the filter unit and if you sanitize the whole system, then there is no need to clean the storage tank separately. However, if there are some issues afterward like a strange taste or smell, and you suspect that the source of them is in the tank, you can clean it more thoroughly.

1) Follow the same steps to depressurize and empty the system.

2) Close the tank valve and disconnect it from the rest of the system but don’t remove the tube that feeds the tank.

3) Drain any water that’s still inside the tube.

4) Use a funnel or a syringe to add the same cleaning solution into the tube. A spoonful or a half should be enough.

5) Reconnect the tubing but don’t let the sanitizer leak out.

6) Make sure that the RO water tap is closed, then open the tank valve and feed the system with water.

7) Let the tank fill and allow the solution so stay inside from 30 minutes to two hours max.

8) Afterward, open the RO faucet to empty the tank. Close the faucet and flush the system two or three times. The solution smell should be gone by now and the tank is clean.

Enjoy your fresh and clean water

Reverse osmosis is a truly great technology that allows you to drink some of the purest water possible. It’s natural that the system itself needs some maintenance. To clean, sanitize and replace parts when the time comes.

Taking care of the system might seem intimidating and might even prove burdensome at first. Yet, with time and practice, it becomes easy. And the water tastes great again.

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