Shut off the water to the sink by turning the water control valve.
Turn the valve of the reverse osmosis system to the off position and open the product faucet to release any water.
Unscrew the filter canisters from the unit by turning with your hands. Use the model number of the filter to order new filters.
Remove the new filters from their box. Hold each filter by the shipping wrapper to prevent contamination of the filter. Screw into place by hand and test the unit.
Unscrew the top of the reverse osmosis unit and pull out the membrane with a set of pliers. Center the new membrane into the center of the system and push it in firmly.