How to Change an RO Filter and Membranes

Reverse Osmsosis Filter and Membrane Changing Procedures:

RO Filter Change Schedule Diagram

Recommended Filter Change Schedule

Sediment Pre-FilterChange every 6-12 months more often in areas with very high turbidity in water.

Carbon Pre-Filter – Change every 6-12 months. This will help to ensure membrane life and quality.

Reverse Osmosis Membrane – Change the reverse osmosis membrane every 24 months.

Carbon Post Filter – Change this filter every 12 months to ensure quality water. Do not wait until taste is a problem.

All reverse osmosis systems require some periodic maintenance to ensure you are getting the same water quality as when the system was new. The most important maintenance for an RO membrane is on time filter changes.

At ESP Water Products, we make it as easy as possible to help you keep track of your RO filter change schedule. Not only do we provide many Replacement Filter Kits to match your system but any time you buy a RO Membrane or Filter from ESP Water Products, we'll send you a reminder when it's time to order a replacement!

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How to Change Reverse Osmosis Filters & Membrane

It is important to ensure that when changing any filters or membrane on your drinking water system, that appropriate sanitation and service procedures are used. The following step-by-step guide will help to ensure those sanitation and service procedures are met.


A. Be certain the proper filter cartridges are used for replacement.
B. The filter cartridges should remain in the original packaging until service to the system is performed.
C. The area around the system should be free from any dirt or rust before servicing. .
D. The person performing the service should wash their hands with soap and water prior to performing any of the service work to prevent the introduction of bacteria to the system.
E. Be aware that running HOT water through the unit can damage the system.

Reverse Osmosis FILTER Change Instructions


Step 1. Turn off the water supply line valve to the reverse osmosis system. Close the ball valve on the reverse osmosis storage tank. Open the reverse osmosis faucet and allow the pressure in the system to bleed off.

Step 2. Place a shallow tray under the filter housing to catch any water that may spill during the filter changing process.

Step 3. Unscrew the filter housing from the filter housing cap and remove the used filter cartridge. (If you have trouble removing the filter housing, a special filter housing wrench is available)

Step 4. Carefully remove the O-ring and place it on a clean surface. Rinse out the disconnected filter housing using warm water and a small amount of liquid soap. Be certain that all of the soap is thoroughly rinsed out of the filter housing before inserting the new filter and reattaching.

Step 5. Wipe the O-ring clean with a soft clean rag or towel and visually inspect for any nicks cuts or abrasions that may cause the O-ring to improperly seat in the filter housing’s O-ring groove. If the O-ring appears damaged, replace it. Additional O-rings are available.

Step 6. Lightly lubricate the O-ring with a silicone lubricant. Insert the O-ring into the O-ring filter-housing groove. It is important to be sure the O-ring is properly seated into the groove as it provides the watertight seal between the filter housing and the filter housing cap.

Step 7. Remove the new filter from the plastic wrap. Measure the new filter to be sure it is the proper length.

Step 8. Place the filter in the filter housing and carefully screw the filter housing back on to the cap of the filter housing, hand tightening only.

Step 9. Turn the water supply valve on. Check the system for leaks.

Step 10. Turn on the reverse osmosis faucet and allow water to flow until the water is clear. Turn off the faucet. System is now ready for use.

Reverse Osmosis MEMBRANE Change Instructions


(for standard replacement membranes)

Step 1. Turn off the water supply line valve to the reverse osmosis system. Close the ball valve on the reverse osmosis storage tank. Open the reverse osmosis faucet and allow the pressure in the system to bleed off.

Step 2. Disconnect tubing from membrane housing. Immediately label which tube came out of which fitting.

Step 3. Unscrew membrane housing from the membrane housing end cap and remove the RO membrane. This may require needle-nose pliers.

Step 4. Rinse the inside of membrane housing with warm water.

Step 5. Insert the new membrane into the housing (o-ring end first) until you feel the o-rings seat into the opposite end cap. You may need to move the membrane in a slight circular motion to center the membrane center tube. If the membrane is not properly seated, untreated water will flow unrestricted through the system.

Step 6. Replace and tighten the membrane housing screw cap. Reinstall the removed tubing to the appropriate fittings.

Step 7. Slowly turn on the water supply line valve until you hear water entering the system. Check for any leaks.

Step 8. Turn on water supply line all the way. Allow filling until a steady drip flows from the reverse osmosis faucet.

Step 9. Turn off the reverse osmosis faucet.

Step 10. Open the valve on storage tank. Check for any leaks. System is now ready for use.