How Long Do RO Membranes Last? Find Out Here!

This page may contain affiliate links. If you buy a product or service through such a link we earn a commission at no extra cost to you. Learn more.

Reverse osmosis membranes are designed for long-term performance and reliability.

Their expected lifespan is incredibly impressive, provided you take care of the system as a whole.

So how long does an RO membrane last exactly? Find out below!

Key Takeaways

  • RO membranes should last between 2 and 5 years on average.
  • How long a reverse osmosis membrane lasts specifically will vary depending on conditions such as the quality of your feed water and adherence to your maintenance schedule.

How Long Do RO Membranes Last?

So, how long do RO membranes last? An RO membrane should last 2-5 years on average.

  • Its longevity mainly depends on the quality of your feed water, the amount of water you use, and if your water is hard or soft.
  • The type of membrane most commonly used in at-home reverse osmosis systems is a TFC membrane, which is very sensitive to chlorine. Therefore adequate pre-filtration is also extremely important to protect your RO membrane. Your feed water quality is affected by how well you maintain the pre-filters it passes through. If you replace all your pre-filters on time, it will help preserve your RO membrane’s life.
  • Cleaning and sanitizing the system and flushing it occasionally could also help.

blue reverse osmosis membrane

How Do I Know When My Membrane Is Bad and Needs Changing?

If you have a reverse osmosis membrane installed in your home, it is important to be aware of the signs that indicate when it may no longer be functioning optimally and needs changing.

Bad Taste & Odor

The most common sign that an RO membrane is bad and needs changing is a decline in the water quality being produced. This could manifest as poor taste or smell, cloudy or murky water, or an increase in sediment or particulate matter. Such impurities may contain potentially harmful substances like bacteria and viruses, which can cause serious health complications if ingested – not to speak of all the potential contaminants invisible to the naked eye such as lead.

Low Water Output

It’s also important to monitor how much filtered water you produce over time. As RO membranes age, they become less effective at processing water; this means that you’ll eventually notice a decrease in output from your system. This could also happen if your system becomes clogged.

If you’re consistently producing lower amounts of water than usual, then it might be time to consider getting a replacement for your RO membrane.

System Draining Water Continuously

If you notice your reverse osmosis system is continuously draining, it could mean your RO membrane is clogged, and it’s time to replace it.

Manufacturer Recommendations

If your manufacturer specifies when the RO membrane of your unit should be changed, then follow those directions, even if it seems to be working just fine.

Low Salt Rejection

Another, very clear sign that your RO membrane has gone bad and needs changing is a significant drop of its TDS or salt rejection rate.

You can measure this by using a TDS meter and following these steps:

  1. Test the TDS of the untreated water. Then test the purified RO water.
  2. Calculate the TDS rejection rate using the formula: Rejection rate in % = (TDS of untreated water – TDS of purified RO water) / TDS of untreated water x 100
  3. If the rejection rate drops below 80%, it is time for a replacement.

How to Maintain a Reverse Osmosis Membrane

You can do some things to maintain your reverse osmosis membrane. It is not really needed providing you are keeping up to schedule with your pre-filter and overall system maintenance, but if you want that extra peace of mind, here are some things you can try.


You can flush your RO membrane to help prevent scaling or fouling. Flushing is a rapid rinse to wash away any impurities which may be accumulating on your RO membrane.

Whole house reverse osmosis systems usually come with an automatic flush system, but they are not common on point-of-use systems as it is easier and cost-effective just to change the membrane when it is no longer functioning correctly.

Chemical Cleaning

Chemical cleaning can be performed on the RO membrane itself. The kind of cleaner you use will depend on what type of matter is accumulating on the membrane. Simply soak the membrane in the chemical solution as recommended by the manufacturer.

plumber installing reverse osmosis system under sink

How to Change an RO Membrane

  1. Wash your hands to prevent contaminating your new RO membrane.
  2. Turn off the cold water and close the valve on the storage tank.
  3. Open the RO faucet to depressurize the system, draining any water until it stops dripping.
  4. Change out the pre and post-filters if required.
  5. Open the RO membrane housing and remove the old membrane. Clean and rinse the housing.
  6. Push the new membrane into the housing until it’s seated tightly. Close the cap.
  7. Turn the water supply back on, open the RO tank valve, open the RO faucet, and let the system flush for a few minutes. Check for leaks.

If you have any thoughts about the question, how long do reverse osmosis membranes last, please don’t hesitate to leave a comment below!

About the Author Gene Fitzgerald

Gene Fitzgerald is one of the founders of BOS and currently head of content creation. She has 8+ years of experience as a water treatment specialist under her belt making her our senior scientist. Outside of BOS, Gene loves reading books on philosophy & social issues, making music, and hiking.
Learn more about .


Information provided on BOS is for educational purposes only. The products and services we review may not be right for your individual circumstances.
We adhere to strict editorial guidelines. Rest assured, the opinions expressed have not been provided, reviewed, or otherwise endorsed by our partners – they are unbiased, independent, and the author’s alone. Our licensed experts fact-check all content for accuracy. It is accurate as of the date posted and to the best of our knowledge.

Leave a Comment: