If you don’t want to call a plumber every time you need to replace the filters in your reverse osmosis system, you can quickly learn how to deal with filter replacement on your own. Reverse osmosis systems usually contain multiple filter cartridges depending on how many filtration stages it’s designed for. Different filter cartridges are replaced at different intervals, however, their replacement largely follows the same process regardless of the reverse osmosis model you have installed in your home.

reverse osmosis system

Before you undertake the task of changing your filters, read our instructions below on how to replace filter cartridges in a reverse osmosis system. We’re going to focus solely on the replacement process of complementary filters (activated carbon and sediment), since we’ve discussed reverse osmosis membrane replacement in a previous article.

First steps

Purchase replacement filters in the correct size and micron rating needed for your system. Have your new filters, a bucket, a dry cloth, a brush and dishwashing soap ready.

Turn off water going into your reverse osmosis water filter and drain the system

Shut off the water going into your reverse osmosis system, then open your kitchen tap downstream to drain the system. Keep the tap open until the water stops flowing.

Unscrew the filter housings

Place a bucket underneath the filter housings to catch all the water that will come out when you remove the filter housings.

Remember which filter goes into which housing

If your filter housings are not labelled to show which type of filter goes where, use a marker to label your housings so you won’t mix up the filters. Except for the replacement of the reverse osmosis membrane, which has to be replaced less frequently than other filters, activated carbon filters and sediment filters will usually have to be replaced at the same intervals. Make sure to change the filters whenever they reach the end of their service life, and avoid using filters beyond the recommended period.

Discard the old filters and clean the filter housings

Use a little dishwashing soap to clean out the filter housings. Make sure your rinse them thoroughly before inserting the new filters. Place the new filters in the correct housings, make sure the O-rings and wet, and then tighten the housings.

Turn on the water to the system and check for leaks

Partially open the inlet valve and wait for the system to fill with water. This will give you time to check for any leaks and shut off the water if you notice any leaks and repair the cause of the leak. Fully open the inlet tap and let the system refill. While it refills, open a tap to release any air that might have been trapped in the system. It takes about 2 hours for the system to refill.

Drain the system and refill

As a last step, you need to drain the system and let it refill once again. If you also replaced the RO membrane, you need to flush the membrane a few more times to make sure there are no foul tastes in your tap water.