3 Tips to Help Maintain Your Reverse Osmosis System

Reverse osmosis is an excellent water treatment method for homes that want high-quality water for their kitchen applications. While maintaining an RO system requires some effort, following a few simple tasks each year can help your system run efficiently and last longer. In this article, you can find three practical tips from John, our Master Water Specialist, to help you maintain your reverse osmosis system.

Why perform maintenance on a reverse osmosis system?

Reverse osmosis (RO) systems are a great asset to have under your sink to provide high-quality water for drinking, cooking, or making ice. To ensure the system continues to remove dissolved solids and the quality of the treated water remains high, RO systems require periodic filter replacements, cleanings, and other maintenance tasks. When properly cared for, an RO system can last for much longer than a decade, so properly maintain your system not only improves your water quality, but it also saves you money in the long run.

1. Change the reverse osmosis membrane and RO filters

No matter which style of system you have, replacing the prefilters, postfilters, and the RO membrane is the most important piece of maintenance you can perform. Quick-change systems, units with drop-in cartridges, and countertop systems all require filter changes at about the same rate.

When to replace reverse osmosis filters and membrane

Consult the below guidelines for replacing your RO prefilters, postfilters, and membrane.

• Prefilters should be changed once every 6 months to 1 year. How much water you use and the incoming water quality affect how long your prefilters can effectively remove contaminants.
• Postfilters should be changed once each year.

• The RO membrane must be replaced once every 2 to 4 years when treating hard water and once every 5 to 7 years when treating soft water.

Prefilters

All RO systems typically have a sediment/carbon prefilter to reduce chlorine so that it does not contact the membrane. Without a carbon prefilter, chlorine would destroy the membrane, forcing the user to replace it frequently. In order to filter effectively, a carbon filter must contain a high capacity for adsorbing contaminants. The best way to ensure that the capacity remains high is by following a regular filter change schedule. A good rule of thumb is to change it at least once each year, but those in areas with high chlorine levels in the city water supply may need to change the prefilter once every six months.

Postfilters

The postfilter polishes the water as it leaves the storage tank on the way to your faucet. Because the water received by the postfilter is treated RO water, you do not need to worry about high chlorine content affect its adsorption capabilities. If the postfilter is changed once annually, you can rest assured that it is doing its job effectively.

RO membranes

The RO membrane is the heart of the reverse osmosis system. It separates the contaminants from the water molecules, leaving you with high-quality water. The quality of the water flowing into your RO system determines how frequently you must change the membrane. A TDS meter can help you check if your RO membrane is functioning properly by allowing you to test its rejection rate. If you notice a downward trend in the rejection rate, the membrane is likely nearing the end of its lifespan. Water-hardening minerals are tough on the membrane, so a membrane used to treat hard water should be changed once every two to three years. A membrane on soft water could last five to seven years if the prefilters are replaced appropriately. If you maintain the health of your reverse osmosis system, it can last ten to fifteen years or even longer.

2. Drain the RO storage tank

You should drain the RO storage tank at least once every two weeks to ensure the membrane maintains proper pressure and that your water stays fresh. To make sure you do not lose access to water when you drain the tank, consider emptying the tank when you go to bed so that the tank can fill up overnight.

Draining allows the RO system to completely turn the water in the tank. When you only use a little bit of water, the system only refills the top portion of the tank. The RO system struggles to put water in that tank, and the rejection is not quite as good as it was when the tank was empty. Draining the tank is particularly important if you do not use a great deal of water because it replaces the water and maintains its quality.

3. Sanitize the RO system

You should aim to sanitize your RO system at least once each year. This prevents bacterial buildup from becoming a problem in the housings, tubing, and storage tank. If your filters must be changed once annually, sanitize the system each time you change your filters. If you must change the filters twice annually, keep track to ensure you are sanitizing at least once every other filter change. To sanitize a reverse osmosis system with traditional housings, follow the steps below.

How to sanitize an RO system

1. Turn off the water supply to your RO system. Also disconnect any lines that are running to your refrigerator if applicable.
2. Empty the remaining water from the storage tank by opening the faucet.
3. Turn off the valve on top of the storage tank.
4. Remove any filter cartridges from their housings and the RO membrane from the system.
5. Reconnect all housings to the system except for the first stage prefilter. Ensure no cartridges are inserted into the housings.
6. Add sanitizer solution to the prefilter that is first in line with the system. We recommend using a Sani-System sanitizer packet, as it is the only EPA registered and NSF approved sanitizer to use with reverse osmosis systems and water softeners. Reattach the housing to the system once the sanitizer has been added.
7. Turn the cold water supply back on. Keep the valve on the storage tank shut off. This will allow the storage tank to fill with water.
8. Let the sanitizer sit for one minute. Because the membrane is not connected to the system, the tank will refill much quicker than when the filters and membrane are installed. Most types of sanitizers must sit for at least one minute to sanitize properly, so let the unit sit for at least one minute once the tank is full.
9. Flush the system. Open the valve on the storage tank and allow the system to flush for at least two or three full cycles.
10. Turn the water supply off. Before you remove the housings to insert your new filters, you must ensure the water supply is turned off. Otherwise, water will flow into your cabinet.
11. Remove the housings and install the new filters and membrane.
12. Allow the system to flush per the manufacturer’s instructions. When a new filter is installed, it must be flushed of any contamination from the manufacturing process. Consult the filter manufacturer’s instructions to flush your filter appropriately.

How to sanitize an RO storage tank

If you have a quick-change RO system, you do not have traditional housings to run sanitizer through. In these cases, you will want to sanitize the RO storage tank once annually. Before you begin, you will need a tank sanitization kit or a sanitizer packet if you already have the other tools available. To sanitize your tank, follow the directions below.

1. Close feed supply valve to the RO unit and open RO faucet to allow all water to empty from the storage tank.
2. Close the tank valve and disconnect the body from the non-valved insert. Shake as much water as you can from the tube.
3. Fill the syringe with the liquid sanitizer and empty it into the coupling body closest to the tank valve so that it enters the tank through the tubing.
4. Connect the body to the valved insert.
5. Open tank valve and feed supply valve and allow the tank to fill for several minutes. If using SaniSystem, you only need to let the water sit for 60 seconds once the tank is full.
6. Close the tank valve. Reconnect the couplings to their original positions. Then open the RO faucet to empty the tank.
7. Close the RO faucet and allow system to fill the tank. This should take 3 to 4 hours.
8. Empty the tank one last time through the RO faucet. The system will be ready for normal use once the tank fills again.

If you have any additional questions, please do not hesitate to contact us.