How Often Should You Change Reverse Osmosis Filters?

Change your RO filters every 12 months. This is an average frequency that most manufacturers recommend because the filters are designed to function best up until this point.

However, this is estimated on daily usage – the amount of water that goes through the system. The manufacturers also state this amount.

Now let’s take a look at why changing the RO filters is important and how you can better estimate when this should be done. 

Related Topic: Cheap Reverse Osmosis Systems

Why you should change Reverse Osmosis filters

The main reason for having the Reverse Osmosis system is to drink purified water. Simply speaking, municipal water is poor quality water and less good for daily consumption.

Basically, the RO system is a set of complex filters that clean your water. Some of the contaminants stay inside those filters. After a period of time, filters get clogged and can’t do the filtering, so the whole system stops being effective. Bacteria can start growing inside the system, and the water tastes bad.

Related Topic: What does reverse osmosis water taste like?

The usual signs that it’s time to replace filters:

• Water has an unusual and unpleasant odor

• Water has an unusual and different taste than before

• The pressure coming from the RO faucet is noticeably decreased

If you suspect any of these RO issues, and there’s nothing noticeably different about the incoming water quality, and there are no water system works in your area, then it’s time to replace the filters.

When to change a reverse osmosis pre-filter

The pre-filter stops dirt, sand, and dust from entering the system. It’s the first barrier against debris and particles, and in a way, it will be the most noticeably soiled. Usually, the lifespan of a pre-filter, under normal conditions, is 12 months. Although if the need arises, it could be changed earlier.

Frequency of changing a carbon filter

Most RO systems have one or more carbon filters that stand second in line. This carbon filter’s primary function is to remove chlorine. So it’s most useful if your water comes from a municipal source. The city water is usually treated with chlorine on a massive scale, to sanitize it

Related Article: Reverse Osmosis Vs Carbon Filter

So, how often should I change a carbon filter? Again, most RO system filters are made to last around 12 months of daily usage, so it’s wise to stick to these guidelines and follow what the manufacturer of your system states.

Related Article: Pros and Cons of Reverse Osmosis

When to change a reverse osmosis membrane

Usually, the reverse osmosis membrane lasts from 2 to 3 years. With hard water and poured water pressure, the effective lifespan of the RO membrane may decrease. Although with proper care, such as flushing your RO system, the membrane can last up to five years.

If you really want to keep track of your water quality, you can measure total dissolved solids with a TDS meter. This is the best way to tell if the RO membrane is working fine.

Read more about RO membrane replacement.

Tips before and after changing RO filters

• The mentioned signs of pourer water quality will develop gradually, so it might be hard to notice them at first until one day you realize that water tastes so much different. 

• After you change the filters, put some paper tape on the casings and write the date when you changed them.

• Do a little tasting test. Before disassembling the RO system, keep some old water. Then, after installing new filters and prepping the system take some new water and compare the taste side by side.

• You should change all the filters on your reverse osmosis system at once. They are made to function as a team, so one changed filter will not do much. Also, this way, you’ll save yourself some work. Unless you really enjoy disassembling RO systems and putting them back together.

• The RO membrane is an exception as it needs to be changed every 2 to 3 years. Although do change it together with the rest of the annual filter change. You can read about How to tell if an RO membrane is bad?

• You need to change filters in popular under-sink RO systems and Best countertop Reverse Osmosis systems.

• I highly recommend that you sanitize your Reverse Osmosis system when you replace filters or on a yearly frequency. Here’s a detailed guide on how to do that and take good care of your RO system.


This is my blog about the ways and solutions that can help you improve your health by taking more value from drinking water. As improving health means a lot to me, I decided to create the Water On Top project with the purpose to reveal the benefits of water, the finest products to take our daily water to another level, and much more great stuff about water that I believe is on top of our nutrition.

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