How to Change Reverse Osmosis Water Filter

When to Change Reverse Osmosis Filters and Membrane

Reverse Osmosis Filter Change Schedule

Recommended Reverse Osmosis Filter Change Schedule

Wondering when to change your reverse osmosis filters? Below is the recommended filter and membrane change schedule, as well as step-by-step instructions for how to replace your reverse osmosis water filters

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 periodic maintenance to ensure water quality remains high. The most important maintenance for an RO system is on time filter changes. Failure to replace RO filters and membranes on schedule can result in a clogged and damaged system.

At ESP Water Products, our goal is to 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 (and save you time and money in finding all the individual filters), but any time you buy an RO Membrane or Filter from us, we'll send you a reminder when it's time to order a replacement!

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How to Install New Reverse Osmosis Filters & Membrane

These are general filter and membrane replacement instructions for most standard reverse osmosis systems. 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. Use this link to learn how to sanitize your RO System including the tubing, storage tank, and fittings.





Preparations Before You Change Your RO Filters:

A. Be certain the proper filter cartridges are used for replacement. Use this link to find the correct filters for your RO system by selecting the correct brand and model of your system. If your RO system brand or model is not listed, or your are unable to determine your brand or model, here are tips to identify your system or contact ESP Water Products Customer Support.
B. The filter cartridges should remain in original packaging until they are ready to install in the reverse osmosis system.
C. The person performing the replacement 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.
D. An RO System Service Kit can help make replacing filters simpler and keep your system in peak performance.

Standard Water FILTER Replacement Instructions

Standard reverse osmosis systems typically have 2-3 vertical filters.

polyspun sediment filter and carbon blocck filter

Step 1. Turn off the feed water supply line valve to the reverse osmosis system.

Step 2. Close the ball valve on the reverse osmosis storage tank. This is typically done by turning the blue ball valve on top of the tank a ¼ turn clockwise.

Step 3. If you have a line going to your refrigerator or ice maker from your RO system, turn off the ball valve on the line going to your ice maker.

Step 4. Open the RO faucet and allow the pressure in the system to bleed off.

Step 5. Place a shallow tray or pan under the filter housing to catch any water that may spill during the filter changing process.

Step 6. Unscrew the vertical filter housings from the cap and remove the used filter cartridge. If you have trouble removing the filter housing, a special filter housing wrench may be needed.

Step 7. Carefully remove the O-rings and place them on a clean surface. Wipe the O-rings clean with a soft clean towel and visually inspect for any nicks cuts or abrasions that may cause the O-rings to improperly seat in the filter housing. If an O-ring appears damaged, replace the O-ring.

Step 8. Rinse out the disconnected filter housings using warm water and a small amount of liquid soap. Be certain that all soap is thoroughly rinsed out of the filter housing before inserting the new filter and reattaching.

Step 9. Lightly lubricate the O-ring with a silicone lubricant. Insert the O-ring into the filter-housing O-ring 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 10. Measure the new filter to be sure it is the proper length. Remove the new filter from the plastic or paper packaging.

Step 11. Place the filter in the correct filter housing and carefully screw the filter housing back on to the cap of the filter housing, hand tightening only.

If your system includes an inline post-carbon filter (typically small horizontal filter on top of system) and/or the reverse osmosis membrane (typically the large horizontal filter on top) and you are also replacing these filters, please jump to the instructions for those filters below. If you are only replacing standard vertical filters, continue the following instructions to complete the filter change process:

Step 12. Turn the incoming water supply valve on and check the system for leaks.

Step 13. Turn on the reverse osmosis faucet. Within a couple minutes, you should get a small steady stream of water or a very fast drip, which means your new filters are working properly.

Step 14. Let several gallons run through the RO system and out the RO faucet with the storage tank valve still closed.

Step 15. Turn off the faucet and open the storage tank ball valve by turning the blue ball valve a ¼ turn counter-clockwise so that the blue handle is parallel with the tubing connected to the storage tank.

Step 16. If the storage tank is empty, it may take several hours for the tank to fill completely. You may hear water running while the tank is filling.

Step 17. If applicable, open the refrigerator or ice maker line, AFTER the tank as completely filled.

Step 18. Your system is now ready for use.

Reverse Osmosis MEMBRANE Replacement Instructions

Standard reverse osmosis systems have one membrane located horizontally above the bracket holding the 2-3 vertical filters.


Step 1. Follow steps 1-5 above, if you have not already done so.

Step 2. Disconnect tubing from membrane housing cap (typically on the right-hand side of the housing) by pushing down on the small ring where the tubing connects to the cap. Press and hold the ring down while you pull the tubing out.

Step 3. Unscrew membrane housing cap from the membrane housing and remove the RO membrane. The membrane has often been there for 1-3 years and may be difficult to pull out. This may require needle-nose pliers to remove.

Step 4. If you would like to clean the membrane housing, disconnect the two tubes on the opposite end of the cap. Label each tube so that you can reconnect each tube to the correct spot later. There are typically two clips that hold the membrane housing in place. Remove the membrane housing from the clips and rinse the inside of membrane housing with warm soap water. Be sure all residual soap is thoroughly rinsed off.

Step 5. Insert the new membrane into the housing with the o-ring end first and the large outer rubber stopper closest to the open cap. Push the membrane in until you feel the o-rings seat securely into the membrane housing. You may need to move the membrane in a slight circular motion to center the membrane and provide some good pressure to ensure the membrane is fully seated. If the membrane is not properly seated, untreated water will flow unrestricted through the system.

Step 6. Replace and tighten the membrane housing cap. Reinstall the removed tubing to the appropriate fittings. To ensure tubing is properly secured, push the tubing into the appropriate fitting as far as possible, then pull lightly on the tube to lock it in place.

Step 7. If you removed the tubing on the opposite end of the membrane housing cap, reinsert each tube into the correct location and secure by following the instructions in step 6.

Step 8. If your system has a horizontal inline filter above or next to the RO membrane that you are replacing, follow the “Inline Post Filter Replacement Instructions” below. If not, return to Step 12 under “Standard Filter Replacement Instructions” to complete the installation process.

INLINE POST FILTER Replacement Instructions

Standard reverse osmosis systems typically have one inline post carbon filter located horizontally above or next to the RO membrane housing. Some inline filters have threaded fittings on each end and others have quick connect fittings. The fittings are sized for either 1/4” or 3/8” tubing.

Inline Filter Example

Step 1. Follow steps 1-5 above, if you have not already done so.

Step 2. Disconnect tubing from each end of the filter, or from fitting connected to each end of the filter, by pushing down on the small ring where the tubing connects to the filter or fitting. Press and hold the ring down while you wiggle and pull the tubing out.

Step 3. If your filter has separate fittings screwed into each end of the filter, unscrew the fittings from the old filter after disconnecting the tubing. Wrap the male threaded end of each fitting with plumber’s tape 2-3 times. Screw the threaded fittings into the new filter.

Step 4. Connect the tubing to the filter by pushing the tubing into the fitting or filter on each end as far as possible. Then, pull lightly on the tubing to ensure the tubing is securely locked in place. (If leaking occurs from these connections after turning on the feed water, it typically means the tubing was not pushed in far enough.)

Step 5. Return to Step 12 under “Standard Filter Replacement Instructions” to complete the installation process. 

NOTE: If you purchased your reverse osmosis water filters from us here at ESP Water Products and need assistance with the install, feel free to call customer support at 877-377-9876 (Monday-Friday 8 am to 5 pm Central). Please have your order number ready. 

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