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How to Clean Reverse Osmosis System (Sanitize)

Jennifer Hansen
Last Updated on
by Jennifer Hansen

Knowing how to sanitize a reverse osmosis system is essential for keeping the water in your home pure.

A good practice for remembering to sanitize your RO system on a regular basis is to sanitize the system when you change the filters. Since the filters require annual replacement, this is a perfect way for the sanitization to coincide.

In addition to sanitizing your RO system on a yearly basis, cleaning your system periodically and cleaning the RO membrane between sanitizations will help keep your water clean, refreshing, and life-enriching year-round.

Reverse Osmosis

Instructions: How to Sanitize Reverse Osmosis System

To sanitize an RO system, follow the steps listed below.

  1. You will need dish detergent, a scouring pad or brush, a bucket, and unscented household bleach (¼ cup).
  2. Wash your hands with hot water and antibacterial soap. You might want to consider wearing rubber gloves, as well.
  3. Fill a bucket with warm dishwater.
  4. Turn off the water line to the RO unit.
  5. Disconnect your ice maker, refrigerator, and other appliances.
  6. To depressurize the system, open the filtered water dispenser.
  7. Wait until the flow of water ends.
  8. Remove all of the filters and the RO membrane. Store the membrane in water to avoid damaging it.
  9. Scrub the interior of the system with dishwater, then rinse thoroughly.
  10. Pour ¼ cup bleach into filter housing 1.
  11. Make sure all the rubber O-rings are in place; replace all the empty housings.
  12. Turn the water line back on.
  13. Open the RO faucet until water begins to stream from it.
  14. Close the RO faucet.
  15. Check the system for any leaks.
  16. Allow the tank to fill.
  17. Leave the bleach and water in place for 30 minutes to two hours.
  18. Flush the system.
  19. Fill the tank again, then flush it again.
  20. If any bleach scent remains, repeat the above step until it is gone.
  21. Turn off the water line again.
  22. Open the faucet to depressurize the system.
  23. Re-install the filters, replacing any that require it.
  24. Check the rubber O-rings again.
  25. Turn the water line back on.
  26. Open the RO faucet to flush the system for a few minutes.
  27. Check once more for leaks.
  28. Close the faucet and allow the tank to fill with water.
  29. Discard the first two tanks of water.
  30. Reconnect your refrigerator, ice maker, and other appliances.

How to Clean Reverse Osmosis Tank

Here is how to clean a reverse osmosis tank between sanitizations:

  1. Wash your hands with hot water and antibacterial soap. You might want to consider wearing rubber gloves, as well.
  2. Turn off the water line.
  3. Open the RO faucet so the system can depressurize.
  4. Wait until the water flow ends.
  5. Close the tank valve.
  6. Disconnect the tank tube, leaving it attached to the tank.
  7. Drain remaining water in the tube.
  8. Funnel ½ teaspoon of unscented household bleach into the tube.
  9. Reconnect the tube, keeping the bleach inside the tube.
  10. Make certain the RO dispenser is closed.
  11. Open the tank valve.
  12. Turn the feed water supply on.
  13. Check for any leaks.
  14. Fill the tank.
  15. Allow the bleach to sit for 30 minutes – 2 hours.
  16. Drain the tank by opening the RO faucet.
  17. Refill the tank and drain it again.
  18. If any bleach scent remains, refill the tank and drain it again. Repeat this step until the bleach smell is gone.

How to Clean Reverse Osmosis Membrane

Cleaning the RO membrane will help keep the system clean for longer by removing the buildup of contaminants.

To clean the RO membrane:

  1. You will need a product designed to clean the type of membrane your RO system uses.
  2. A cellulose membrane requires a cellulose acetate membrane cleaner.
  3. A thin film membrane requires a silicate product specially designed to remove silica only, an acid cleaner for removing mineral scale, an alkaline cleaner to remove organic material, and an anionic surfactant cleaner to remove mildew and mold. You can use any combination of these products, depending on the state of your membrane and the quality of your water.
  4. Wash your hands with hot water and antibacterial soap.
  5. Wear rubber gloves and protective eyewear.
  6. Turn off the water line.
  7. Disconnect the membrane housing.
  8. Open the gasket and remove the membrane.
  9. Set the membrane on a clean, disinfected surface.
  10. Fill a bucket with water and mix the chemical cleaner as directed on the packaging.
  11. Soak the membrane in this solution for an hour (if the packaging directions indicate a different amount of time, follow them).
  12. Remove the membrane from the solution after the appointed amount of time.
  13. Rinse the membrane in clean water.
  14. Place the membrane back into the housing.
  15. Put the housing back in place in the RO system.
  16. Hook your system back up to the water line.
  17. Turn the water line back on.
  18. Flush the system by running water through it for 15-30 minutes.

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About Jennifer Hansen
Jennifer Hansen
Jennifer is a clean water enthusiast and the lead editor of Water Filter Spot and created this website several years ago to share information that she's been researching in this industry for over 20 years.Jennifer studied environmental resource science in college and studied Western US water issues, including water policy, water rights, water pollution and environmental concerns.
Jennifer Hansen
2 Comments
  1. Hi Jennifer, Thank you for this very informative article! My husband and I live in Naples, Florida. We recently purchased a home and have a well with a whole house RO system. We are learning by doing, as it were. We know next to nothing about this complex system. So thanks again for the excellent description and advice.
    Regards, Pat and Kevin

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