The membrane in your Reverse Osmosis Drinking Water System does not need to be replaced as often as the rest of the filters but depending on your water’s chemistry, if you have a water softener or not and how much water you put through the system the membrane will need to be replaced anywhere from every 2 to about 8 years. The best way to tell if it needs replacement is by testing the TDS (Total Dissolved Solids) of your water coming through your reverse osmosis faucet and comparing it to the TDS of your household water. The TDS of the water coming through your RO faucet should be about 10% of the raw water. If it is above 20% of your tap water, you need to replace the membrane.
Once you have determined that the membrane needs replacement shut off the tank and the water supply to the RO and release the pressure by opening the faucet. Remove the tubing from the end of the membrane housing and pull out the membrane with a twisting motion using a pair of needle nose pliers. Lubricate the O rings and main seal with clear plumbers silicone grease and slide membrane into the housing making sure it is fully seated. Put the cap back on the membrane housing, slowly turn on the water supply and open the tank allowing the RO to refill. After 2 hours open the faucet to purge the air from the system and flush the membrane. Repeat two more times pausing for 2 hours in between for the tank to refill and then the water is ready to drink.
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