Push and hold the collet against the quick-connect fitting and pull out the tubing.
Repeat on the other end.
Remove the cartridge and install the replacement filter; check the arrow for the flow direction.
Reconnect by pushing the tubing into the fitting and pulling back on the tubing to secure the connection.
Turn the water supply back on.
Open the RO tank valve.
Open the filtered water dispenser and let the system flush for a few minutes.
Check for leaks.
Close the faucet and let the tank fill.
Discard one or two full water tanks. Any discolored water should clear after the first flush.
How to Replace the RO Membrane
Check the manual for how to replace the membrane for your specific under sink reverse osmosis system.
Wash your hands.
Turn off the water supply and close the storage tank valve.
Turn on the RO faucet and let it drain until all the drips stop, then close it.
Remove the water line from the cap of the membrane housing. Push and hold the collet against the quick-connect fitting and remove the tubing. Some systems may have a plastic clip to remove too.
Turn the membrane housing cap clockwise to remove it, using a filter wrench or strap if needed.
Remove the old membrane. Use needle-nose pliers if needed.
Clean inside the membrane housing with warm water and dish soap, and sanitize with a suitable disinfectant or unscented bleach.
Push the new RO membrane into the housing, with the end with the two black O-rings to go in first. Avoid touching the membrane with your bare hands.
Double-check that the O-rings are in good condition and replace them if needed.
Screw the housing cap back on, being careful not to overtighten it.
Push the tubing into the cap fitting to reconnect the membrane. Pull back on the tubing to secure the connection.
Turn the water supply back on and open the RO tank valve.
Flush the system for a few minutes, and check for leaks.
Turn off the faucet and let the storage tank fill.
Discard one or two tanks of water before use to eliminate any preservatives in the membrane, which may cause a strange taste or smell.
When to Change the Filters of Your Under Sink RO system
Under sink RO filters need to be changed on a regular basis, or you run the risk of drinking contaminated water. Factors such as the condition of your feed water and how much water you use will affect how often the filters need changing.
As a general rule, sediment and carbon pre-filters should last 6-12 months, and a carbon post-filter can last 12 months to 2 years.
Cheap filters or low-quality filters may need to be replaced more frequently.
Signs that your filters may need replacing include:
Decrease of the purity of your water (unpleasant tastes, smells, or colors)
A drop in water pressure and decreased water flow.
Sediment pre-filter – 6-12 months. More frequently if the feed water has high turbidity levels.
Carbon pre-filter – 6-12 months.
Reverse osmosis membrane – 2+ years.
Carbon post-filter – 12 months. Do not wait until the taste of the water changes.
If you have any questions about under sink reverse osmosis filter replacement please don’t hesitate to leave a comment below!
About the Author Gene Fitzgerald
Gene Fitzgerald is one of the founders of BOS and currently head of content creation. She has 8+ years of experience as a water treatment specialist under her belt making her our senior scientist. Outside of BOS, Gene loves reading books on philosophy & social issues, making music, and hiking.
Learn more about Gene and the rest of the BOS Team.
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