How to Change RO Filters

RO filters and membranes

When to Change Reverse Osmosis Filters and Membrane

All reverse osmosis systems require periodic maintenance to ensure water quality remains top notch. 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.

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 prefilter phase

SEDIMENT PREFILTER
This pre-filter stage is designed to strain out sediment, silt, and dirt and is especially important as the sediment filter protects dirt from getting to the delicate RO membranes that can be damaged by sediment. Learn more about sediment filter. Change this filter every 6-12 months-- more often in areas with very high turbidity in water.

Carbon prefilter phase

CARBON PREFILTER
The carbon filter is designed to remove chlorine and other contaminants that affect the performance and life of the RO membrane as well as improve the taste and odor of your water. Change the carbon filter every 6-12 months. This will help to ensure membrane life and quality.

Reverse Osmosis membrane phase

REVERSE OSMOSIS MEMBRANE
The semi-permeable RO membrane in your RO system is designed to allow water through but filter out almost all additional contaminants. Change the reverse osmosis membrane every 24 months.

Polishing filter phase

POLISHING FILTER
In a four-stage RO System, a final post filter (carbon filter) will “polish” off the water to remove any remaining taste and odor in the water. Change this filter every 12 months to ensure quality water. Do not wait until taste is a problem.

RO purified water

How to Find Your Correct RO Replacement Filters

At ESP Water Products, our goal is to make it as easy as possible to replace 1-year annual filter replacement kit RO wateryour RO filters. We provide Replacement Filter Kits for more than 100 RO systems, designed to save you time and money by bundling the necessary annual filter change items together.

If there is no label on your RO system and you're unsure of your system's brand and model, we'll take you through the steps to identify your Reverse Osmosis drinking water system.

Find Your Filter & Membrane Replacements

Before Installing RO Filter Replacements

Before you begin installing filter replacements in your reverse osmosis system, make sure you have the correct filter cartridges. certain the proper filter cartridges are used for replacement. If you are unable to determine your system's brand or model, we provide tips to identify your RO system or contact ESP Water Products Customer Support.

  • The filter cartridges should remain in original packaging until they are ready to install in the reverse osmosis system.
  • 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.
  • An RO System Service Kit can help make replacing filters simpler and keep your system in peak performance.

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.

Standard RO Filter Replacement Instructions

1. Turn off water

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

2. Close ball valve

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.

3. Shut off refrigerator connection

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 or refrigerator.

4. Release system pressure

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

5. Prepare drip pan

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

6. Remove filters from housings

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.

7. Inspect o-rings

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.

8. Clean filter housings

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.

9. Lubricate o-rings

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.

10. Insert the new filter replacements

Remove the new filter from the plastic or paper packaging. 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.Standard reverse osmosis systems typically have 2-3 vertical filters.

11. Turn water line back on

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

12. Turn on RO faucet 

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

13. Open storage tank

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.

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.

14. Reconnect refrigerator

If applicable, open the refrigerator or ice maker line, AFTER the tank is completely filled.

Your system is now ready for use. Please refer to our RO Troubleshooting Guide for answers to common questions and issues.


Reverse Osmosis Membrane Replacement Instructions

Standard reverse osmosis systems have one membrane located horizontally above the bracket holding the 2-3 vertical filters.polyspun sediment filter and carbon block filter

1. Turn off water

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

2. Close ball valve

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.

3. Shut off refrigerator connection

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 or refrigerator.

4. Release system pressure

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

5. Prepare drip pan

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

6. Disconnect membrane tubing

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.

7. Unscrew housing cap

Unscrew membrane housing cap from the membrane housing and remove the RO membrane. The membrane has often been there for ~2 years and may be difficult to pull out. This may require needle-nose pliers to remove.

8. Clean filter housings

We recommend cleaning the membrane housing at this time. 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.

9. Insert new membrane

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.

10. Insert the new filter replacements

Remove the new filter from the plastic or paper packaging. 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.Standard reverse osmosis systems typically have 2-3 vertical filters.

11. Replace cap and tubing

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.

If you removed the tubing on the opposite end of the membrane housing cap, reinsert each tube into the correct location and secure.

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.

12. Turn on water line and RO faucet 

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

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

13. Open storage tank

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.

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.

14. Reconnect refrigerator

If applicable, open the refrigerator or ice maker line, AFTER the tank is completely filled.


How to Replace an Inline RO Post Filter

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.

Reverse Osmosis Inline Filter

1. Turn off water

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

2. Close ball valve

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.

3. Shut off refrigerator connection

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 or refrigerator.

4. Release system pressure

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

5. Prepare drip pan

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

6. Disconnect filter tubing

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.

7. Unscrew fittings

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.

8. Connect tubing

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.)

9. Turn on water line and RO faucet 

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

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

10. Open storage tank

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.

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.

11. Reconnect refrigerator

If applicable, open the refrigerator or ice maker line, AFTER the tank is completely filled.

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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