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 change 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
- Make sure you have all the required replacement filters and membranes.
- The replacement filter and membrane should remain in their original package until they are ready for installation.
- Make sure your hands are clean.
- Turn off the water supply.
- Turn off the storage tank valve.
- If you have a line going to the refrigerator or icemaker from your RO system, make sure you turn it off.
- Open the RO faucet to drain off all the water in the system.
- 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.
- 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.
- 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.
- Add a new filter or membrane to their respective housings.
- 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.
- 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).
- Check for leaks and let the system flush for a few minutes.
- Turn off the RO faucet.
- Turn on the storage tank valve.
- Wait for the tank to refill.
- 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
- Repeat steps 1 to 7 above.
- Remove the tubing from the membrane housing cap.
- Remove the old membrane from the housing.
- Clean the housing using warm, soapy water and rinse thoroughly.
- Insert the new membrane into the housing and make sure the O-ring is in place and in good condition.
- Return the membrane housing to the system.
- Reinstall the tubing. Ensure the tubes are securely connected.
- 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.