How to Replace Reverse Osmosis Filters and Membrane

The reverse osmosis system uses filters and an RO membrane to purify water. Both membranes and filters do not last forever after treating water; sometimes they require replacement for the system to operate effectively. In this article, you will learn step-by-step how to replace reverse osmosis filters and membrane.

When to replace reverse osmosis filters and membrane

A standard under-sink reverse osmosis system treats water in four stages. Each stage has a different cartridge that is designed to remove specific contaminants and replace them after a period of use. The filters involved in each stage and its life span include:

• Sediment filter: this is the first stage that removes particulates. The filter is changed every 6 to 12 months.
• Carbon pre-filter: This is the second stage that removes chlorine taste and odor. The filter is changed every 6–12 months.
• RO membrane: This is the heart of the system that removes heavy metals and TDS. The membrane is changed every 2-3 years.
• Carbon post-filter: this is the final stage and the polishing stage that helps remove any remaining taste and odor. The post-filter is replaced every 6-12 months.

Step-by-step procedure on how to replace Reverse osmosis filters

1. Make sure you have all the required replacement filters and membranes.
2. The replacement filter and membrane should remain in their original package until they are ready for installation.
3. Make sure your hands are clean.
4. Turn off the water supply.
5. Turn off the storage tank valve.
6. If you have a line going to the refrigerator or icemaker from your RO system, make sure you turn it off.
7. Open the RO faucet to drain off all the water in the system.
8. Unscrew the housing and remove the old membrane and filters from the housing. If you have a problem unscrewing the housing, use a wrench to assist with that.
9. At this point, clean the housing using dish soap and clean warm water. You can sanitize the filter and membrane housing using unscented bleach. Rinse the housing thoroughly.
10. Check for the O-Ring to be in the right condition. If it’s not in good condition, replace it with a new one. Lubricate the O-ring with silicone lubricant. An O-ring provides a tight seal between the housing and the housing cap. This helps prevent leaks.
11. Add a new filter or membrane to their respective housings.
12. Return the housing to the system. You can use a wrench to tighten the housing, but make sure you do not over-tighten. Over-tightening can flatten the O-ring and crack the housing, leading to a leak.
13. Turn on the water supply and RO faucet (Note: at this time no water is entering the storage tank; remember it is still in bypass mode).
14. Check for leaks and let the system flush for a few minutes.
15. Turn off the RO faucet.
16. Turn on the storage tank valve.
17. Wait for the tank to refill.
18. Discard 2 full tanks of water before, but this depends on the system. You can use water for watering plants or cleaning.

RO membrane replacement procedure

1. Repeat steps 1 to 7 above.
2. Remove the tubing from the membrane housing cap.
3. Remove the old membrane from the housing.
4. Clean the housing using warm, soapy water and rinse thoroughly.
5. Insert the new membrane into the housing and make sure the O-ring is in place and in good condition.
6. Return the membrane housing to the system.
7. Reinstall the tubing. Ensure the tubes are securely connected.
8. Continue with steps 13 to 18 above.

I am hoping the above step-by-step will help replace reverse osmosis filters and a membrane with ease.

Watch the video below from APEC to help you with how to replace reverse osmosis filters and a membrane.