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.
Familiarizing yourself with the maintenance procedures involved in using a reverse osmosis system is important if you want to get the most out of it.
Most of the time, maintaining an RO system will be an easy task, especially when it comes to cleaning and swapping out parts.
One question that many new owners tend to ask is how often they should replace their reverse osmosis filters. The answer depends on your usage habits and water contamination levels. Here’s what you need to know.
As a rule of thumb, sediment and carbon pre-filters should be replaced once or twice a year. This depends on the specific model and the manufacturer’s guidelines. The carbon post-filter can be replaced once a year, while the RO membrane can last for two to five years on average.
Different parts of the system need to be replaced at different frequencies. You should familiarize yourself with the schedule for every component of your system and ideally keep track of it in a dedicated calendar so you can be sure that you don’t miss any pending replacement.
You should replace the sediment pre-filter of your RO system once every 6-12 months. The exact frequency depends on the manufacturer’s recommendation, your usage habits, and the level of contamination in your water supply.
The same goes for the carbon pre-filter. 6-12 months is a good estimate for its replacement frequency. Keeping this filter in a good condition is important for eliminating foul odors and tastes from your water.
The carbon post-filter of your RO system can last a bit longer. Typically, you will only need to replace it once a year at most. If you notice your water developing an unusual, unpleasant taste, that’s probably a sign that you need to replace the carbon post-filter.
As we mentioned earlier, you won’t need to replace your RO membrane more often than every two to five years. To determine whether it’s time to swap it, you will need to run a test with a specialized meter to determine your level of TDS (Total Dissolved Solids) in the permeate water.
You will need to take two samples – one from treated water, and one from untreated water. Then, you can calculate the rejection rate with the following formula:
(untreated TDS – purified TDS) / untreated TDS x 100
The resulting number will be your rejection rate as a percentage. If it’s below 80%, you need to replace your RO membrane.
Different scenarios call for different RO filter replacement schedules. If your water is more heavily contaminated, you’ll probably need to replace your membrane and filters more often. The same goes for large households with more active water usage. If you have a large number of people using filtered water every day, this can put more strain on the RO system, requiring more frequent filter replacements.
You can follow the guidelines from above for your filters, but when it comes to the RO membrane itself, you should always run a test before deciding to replace it.
There are also some signs that can alert you that it’s time to replace your RO filters or membrane. You should watch out for those, and if you notice anything out of the ordinary, run a test to verify the current situation before taking any further steps.
Bad taste and odors in your purified water could indicate that not all contaminants are being removed properly. It could also be caused by fouling of the filter cartridges. In any case, this is a sign that you should consider replacing your filters soon.
If your filters get clogged, this could lead to a drop in your water pressure. Furthermore, you might see your tank not filling properly. If this happens, make sure to check the filters to see if they are up for a replacement.
Once your membrane gets clogged too much, you will see more water getting rejected and ending up down the drain. This results in pressure that’s constantly too low to fill the tank, and as a result, your system never shuts off.
When the RO membrane stops doing its job properly and doesn’t reject contaminants as it should, you will see your TDS level increasing. As we mentioned above, you can perform a test with a meter and use a simple formula to determine if that’s the case.
It’s a good idea to keep some reminders about each filter’s replacement. You can use your phone to set an alert in your calendar, for example. As long as you remember to do this immediately after replacing the filter, you will get automatically notified when it’s time for another replacement. This can relieve you of the pressure of having to keep track of those schedules manually.
If you don’t replace your reverse osmosis filter elements frequently enough, the system will eventually get clogged and won’t work as intended. Also, your drinking water will become more and more foul as various contaminants accumulate in it. These can include harmful ones like pathogens, making it even more important to keep track of your system on a regular basis.
Even if you don’t notice any unpleasant effects immediately, you’ll still end up dealing with reduced pressure which can lead to a lot of wasted water as the RO system is unable to function properly. You will sooner or later see your water bill increasing significantly.
To install new filters in your RO system, the general process is the same for all filter types.
Most people should be able to replace and install filters in their RO systems on their own. You generally don’t need to hire a professional for that, although if you don’t feel confident using tools and working on your appliances, it could make sense to call an expert.
Otherwise, you should just roll up your sleeves and take the hour or so to do the job yourself. You’ll also learn a thing or two about the way your RO system works, and you’ll be in a better position to maintain it in the future!
If you have any questions about how often to change RO filters please don’t hesitate to leave a comment below!
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.