Filter systems that aren’t equipped with a filter lifetime tracker system or a water quality analysis system, aren’t very forthcoming with information on when to replace your water filter cartridges or how much longer you can use them in your water filter system.

In the absence of such tracking and analysis tools, you must rely on the manufacturer’s indications, which can be rather vague sometimes.

What this essentially means is that you may be replacing your filter cartridges too often or less often than you should. So, how do you know when to replace filter cartridges if you don’t have a built-in filter lifetime tracker system?

There are a few simple ways to determine if it’s time to replace your filter cartridges, which we’re going to discuss in this article and help you maximise the service life of your cartridges in a safe way.

How to Replace Filter Cartridges?

Most systems are very straightforward when it comes to filter replacement. You replace cartridges either by taking out the cartridge from a filter housing or, if your filter system comes with quick-change filter cartridges, you untwist the entire filter cartridge (housing and all) and replace it with a new one.

Quick-change filter cartridges have the advantage of offering a cleaner and faster filter exchange experience, therefore, most users prefer them over traditional cartridges that must be removed from their filter housing.


Filter Lifetime Tracking Systems

Filter lifetime tracking systems are tools built-into the filter system that track filter and water usage and feature a countdown system letting you know how long you have until filter cartridge exchange is due.

For example, the BMB-30 NOVA PRO Direct Flow 9-Stage Reverse Osmosis System is equipped with a with a digital controller with Smart Water capabilities that tracks filter lifetime along with other water quality parameters.

These are handy tools that will help you remember when to replace filters to keep your drinking water safe and clean. Even in the absence of these sophisticated tools, you can still determine whether it’s time to replace your cartridges.


When is it Time to Replace the Cartridges in Your Filter System?

All filters come with a filter lifetime that’s determined by the manufacturer. Unless they’re specially designed, long-lasting cartridges, most cartridges last anywhere between 3 to 6 months.

The service life indicates the longest time during which a cartridge can efficiently remove the contaminants it’s designed to remove and at the rate at which it’s designed to do so.

The filter lifetime is also the period for which cartridges can be used without fear of recontamination or bacterial overgrowth.

Over time, the filter medium that makes up these cartridges becomes saturated or clogged with various contaminants, which means that after a while they can no longer perform as they should.

Since contaminants are no longer removed from your drinking water, a new filter cartridge is needed. This is where regular filter maintenance becomes extremely important.

Here’s when you must replace cartridges in a water filter system:

  1. When cartridges reach the end of their service life as determined by the manufacturer (this is the period indicated on the packaging or user manual of the filter system/cartridge);
  2. When water pressure drops, or you notice filter clogging issues (You must replace your cartridges even if you experience these problems before the end of filter lifetime);
  3. When there’s a known water contamination issue (E.g. you get a water boil notice from the water supplier. In these situations, it’s best to perform a filter change after the boil notice has been lifted).


Types of Filter Cartridges

We could categorize filter cartridges according to multiple criteria, however, for the purposes of this article, we’re looking at reusability.

Generally, filter cartridges should not be reused under any circumstances. Most filter cartridges are single-use, meaning they cannot be reused after they reach the end of their service life. Therefore, they should be discarded and replaced with new ones.

Even though single-use filter cartridges are the norm, there are some filter cartridges that can be reused albeit for a limited number of times.

One example of reusable filter cartridges are ceramic filter candles, which can be washed under running water and reused for a maximum number of times and for a limited period only.

Ceramic filter candles are used in gravity filters such as the ones manufactured by Doulton, Berkey, and Coldstream.


How to Make Your Filter Cartridges Last Longer?

Before we delve into the different ways to get the best out of your water filter cartridges, we should mention that replacing filter cartridges on time is a serious issue and you shouldn’t postpone it.

Forgetting to replace your filters or postponing replacement for a long period can have unfavourable consequences including water contamination issues caused by the accumulation of contaminants in the filter media, bacterial growth, strange smelling or strange tasting water.

However, there are safe ways to get the best out of your filters, namely:


  1. Changing pre-filters regularly so that more expensive downstream filters are protected (e.g. in reverse osmosis filters sediment pre-filters and carbon block pre-filters remove chlorine and sediments that may damage or clog the more expensive reverse osmosis membrane shortening its service life);
  2. Cleaning cleanable filters to prolong their life, without reusing the filters more times that it’s recommended by the manufacturer;
  3. Buying filters with a micron size appropriate for the type of contamination issue you’re dealing with (E.g. buying a sediment filter with a small micron rating when you have larger sediments in your water is counterintuitive since cartridges will clog faster, which means you need to replace them more often);
  4. Monitoring water quality (Something as simple as monitoring changes in the quality of your water – e.g. water clarity, taste, and odour – can help you determine whether you need a filter replacement).



Although sophisticated filter lifetime tracking systems are certainly a welcomed feature on residential filter systems, there are other ways to tell if the cartridges in your filter system need replacement or not.

We hope this article will help you better manage your filter system’s maintenance and get the best out of your water filter.


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