How to Change Reverse Osmosis Filters – Proper Replacement!

Why You Should Know How to Change Reverse Osmosis Filters

Your reverse osmosis filters don’t last forever and regular maintenance is the key to ensuring the system is functioning properly. In this guide, we will be taking a look at the necessary information, including how often you should change the filters, and also how to actually change the filters on your own.

Do keep in mind that we are discussing based on the requirements of RO systems, on the whole, so please check your user manual first just to be sure. That said, let’s jump right into it.

How Often Should You Replace Reverse Osmosis Filters?

Before we take a look at how often you need to change reverse osmosis filters, you should keep in mind that the duration is heavily dependent on the condition and quality of your water supply, as well as the water usage of your household.

Sediment Pre-Filter

The sediment pre-filter is the first filter stage of an RO system. This filter is a little bigger in size and is meant to remove suspended contaminants such as sand, dirt, dust, and rust. The main purpose of a sediment filter is to prevent the large sediments in your water from clogging up and damaging the filters in later stages.

If you already have a decent water softener that is capable of catching most of the larger mineral buildup, then you can expect to change the sediment filter once a year. However, if you are not using a water softener, then your filter is most likely working harder than it’s supposed to. In that case, we would recommend you to check it every 6 months.

Carbon Pre-Filter

The next filter will be the carbon filter. The purpose of this filter is to remove contaminants like chlorine, some particles, and volatile organic compounds. These things are unwanted because it causes health risks and it gives your water a funny taste and smell. The recommended time frame to change your carbon filter is at least once every 6 to 12 months.

RO Membrane

The key to a reverse osmosis system is the reverse osmosis membrane. The RO membrane is an important part of the reverse osmosis system because it is responsible for the removal of most of the impurities, both dissolved and surface contaminants, from your water. Reverse osmosis systems are able to remove more than 99.9% of all total dissolved solids (TDS) thanks to the RO membrane.

Thankfully, the reverse osmosis membrane has a decently long lifespan of 2 years on average. There are even some systems with a membrane that lasts for up to 4 years.

Carbon Post/ Polishing Filter

Finally, we have the carbon post-filter which is responsible for removing any lingering water contaminants and microscopic particles that exist in very low concentrations. This post-filter can also remove any contaminant that may have leached into the water while it was in the storage tank. You can think of the post-filter as the “finishing touches” that ensure your water is clean and safe to drink.

Since the post-filter doesn’t come into contact with that many undesirable matters, it will usually last longer than pre-filters. Generally, you will need to replace the post-filter once 6 months to a year. Even though this isn’t one of the filters that require regular replacement, it is still a good idea to get it changed when it needs to be, especially if your system comes with a water storage tank.

How to Change Filters in a Reverse Osmosis System

Now that you’re aware of how often you need to change the reverse osmosis filters, it is time you learn to actually change them on your own. While the filter change process for a system varies from manufacturer to manufacturer, most of them are still designed to be as simple as possible.

How to Replace Carbon & Sediment Filters

Here are the steps that you can follow to replace the carbon and sediment reverse osmosis filters:

Step 1: Make sure the correct replacement filters are purchased

The first and most important thing that you should do before you begin the filter replacement process is to make sure you bought all the filters correctly. For peace of mind, we would recommend you to buy from the company that manufactured your reverse osmosis system, or from the brand’s Amazon page.

You can also consider buying products from brands that are not as well-known but still fit in your system. However, it can be quite a risky investment, so be sure to check the customer reviews of those products thoroughly before you buy them.

Step 2: Wash your hands

To ensure that you’re not contaminating the filters with the germs on your skin, you need to wash your hands thoroughly. When you’re washing your hands, be sure to use soap and water to get rid of those germs.

Step 3: Turn off the water supply

By turning off your supply line, you prevent any more water from passing into the system. If your system comes with a storage tank, then you’ll need to close the ball valve. Moreover, if the system is connected to an ice maker or a refrigerator, you should close off access to this valve as well.

Step 4: Drain the waterline

Once the supply is turned off, you need to drain the remaining water out of the system. To do so, switch on the designated RO faucet and empty out the water. To prepare for potential leaks, you can place a bucket or a tray beneath the filter housing so it catches any drips.

Step 5: Remove the old filters

After the remaining water is drained, unscrew the filters that need to be changed from the filter housing and dispose of them properly. Most filters nowadays can be recycled, so be sure to check with the manufacturer for confirmation. If the filters are a little stiff and difficult to unscrew, you can try using the wrench provided by your manufacturer.

Step 6: Remove and clean the black rubber O-rings

Next, remove the filter housing and the system’s O-rings. Once they’re out, use a cloth to wipe them and place them on a clean surface. This is also a good time to inspect each O-ring and ensure that they are in a good condition. If not, you should have them replaced too.

Step 7: Clean the filter housing

Use soapy water to clean the inside of the system’s filter housing. Once cleaned, be sure to dry the housing and make sure that all the soap is removed, then reattach the housing to your unit.

Step 8: Lubricate the O-rings

Ensure that each O-ring is properly lubricated and insert them back into where you removed them from. You should also make sure that they are in the correct position to prevent leaks.

Step 9: Insert the new filters

Get the filter replacement out from its packaging, then insert the filter replacement into the respective housing and screw it in place. You can usually tighten it by hand or use the filter wrench that was given, but be sure to not over-tighten them.

Step 10: Turn on the water

Once everything is in position, you can turn on your water supply slowly and check to see if there are any leaks. If there are any, tighten the replacement filters a little more or inspect to see if the O-rings are in the correct position.

Step 11: Flush and test the system

Get the faucet switched on and wait for the water to flow through. If water is flowing smoothly, it means that the filters are installed in a correct manner and the reverse osmosis system is ready for use. However, if your system comes with a water storage tank, do not let water flow into it yet.

Step 12: Fill up the storage tank (if applicable)

With the water flowing from your faucet for about 5 minutes, you can turn off the faucet and open the ball valve connecting to the holding tank. Wait for the holding tank to fill, then open the valve that connects to your fridge or ice maker. At this point, your reverse osmosis water filter should be ready to use once again.

How to Replace the Reverse Osmosis Membrane

The procedure for replacing your RO membrane is slightly different from the previous filter replacement. Here’s how it goes:

Step 1: Cleaning and prepping

Follow steps 1 to 4 as mentioned above before you start the installation.

Step 2: Disconnect tubing

On the right side of your housing, there should be a tubing that connects to the membrane housing cap. Disconnect this tubing and ensure that you are pressing down on the small ring around the tubing as you’re disconnecting it.

Step 3: Get rid of the old membrane

Unscrew the cap from the top of the RO membrane housing and slowly extract the membrane out of it. You might need to use needle-nose pliers for removing the membrane if it’s wedged inside the housing.

Step 4: Cleaning the membrane housing

When it comes to cleaning the membrane housing, it is advisable to take a little more time, since you are unlikely to clean it again for another 2 years. You can do this by disconnecting the tubes on the other end of the cap. As a reminder, you can color-code or label them so you remember where each one goes after you’re done.

Wash the inside of the membrane housing using a bit of soap and warm water. Then, rinse it under your faucet and dry it thoroughly before you reattach it to your RO system.

Step 5: Install the new RO membrane

Get the replacement membrane out of the packaging and push it into the housing, while checking that the end with the O-rings is going in first. Keep pushing it in until contact with the base is made. You should use a bit more force when you’re pushing to make sure the new membrane is properly in place.

Step 6: Replace the membrane housing cap and tubing

Once the previous procedure is completed, you can now screw the cap back onto the membrane housing and connect the necessary tubing that was disconnected earlier. You should also take note to push the tubing into the fitting until it cannot go any further to ensure that it is secured and will not leak. Give it a quick pull to make sure that it’s locked in position.

Step 7: Flush, test, and run the system

Follow steps 10 to 12 from above to complete the installation and your reverse osmosis water filtration system should be running properly again.


Now that you’ve come to the end of our guide, you should be able to change reverse osmosis water filters on your own with much more ease. However, if you are still experiencing problems with your reverse osmosis system, it would be wise to consult with a plumbing expert to identify and solve the issue.

FAQ on changing reverse osmosis filters

How do I know if my reverse osmosis filter is bad?

If your reverse osmosis filter is bad, it would be a clear sign for a filter change as soon as possible. However, you might be wondering how to tell if a reverse osmosis filter is bad. Well don’t worry, because you can look out for the following signs to know if your water filter is no good:

  • Low water pressure. Reverse osmosis systems will usually provide you with fresh water almost instantly. However, if you need to wait for quite a while to fill up a glass of water due to low water pressure, this is a sign that the reverse osmosis filter needs changing.
  • Poor taste. When your water starts giving you weird tastes, then it is a signal that RO filters need changing.
  • Low efficiency. When your reverse osmosis filter isn’t working efficiently, you can expect that changing to a new filter will help. You can pay attention to the sound of the system running, and if it seems like it’s always running, there’s a high chance that it’s not efficient anymore, and changing the water filter will certainly help.

To avoid drinking water that has poor quality, you can mark your calendar to remind yourself when the water filters of your reverse osmosis system need changing. Maintaining it on a regular basis also prolongs the service life of your unit.

How much does it cost to replace an RO filter cartridge?

This is heavily dependent on the brand you’re buying from. Generally, a pack that comes with all the necessary filters will cost around $60 to $100, while RO membranes on their own go for $30 to $75.

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