Changing filters and water filter performance

Your water filter’s performance is correlated with the quality of the water filter cartridges within the system and their timely replacement when they reach the end of their service life.

If you notice that your water filter’s performance is not up to par anymore, it may be a sign that your filters need changing. Water filter cartridges within a water filter system can only filter water for so long before they become saturated with contaminants, which makes them unable to produce high quality drinking water.

As a result, your water filter’s performance may take a hit. Problems with water flow, bad tastes and odours in your drinking water are some of the few signs that your water filter is no longer operating at peak performance. In most cases, this is due to filter cartridges being saturated with contaminants or becoming clogged because of contaminants.

In this article, you will learn about the importance of changing filters on time, how to replace your filters, and the consequences of neglecting to carry out timely filter changes.

Why Change Your Filters?

Changing filters is an integral part of your water filter’s servicing. Water filters are designed with a certain filtration capacity, that is, the amount of water the filter can filter in a given amount of time.

The filtration capacity varies from filter cartridge the filter cartridge. Some filters can last up to 36 months others need to be replaced as frequently as every three months.

Sometimes, even water filters with a high filtration capacity and long service life may need to be replaced more often than recommended by the manufacturer. This usually happens when there is a mismatch between the type of filter you use and the contaminants present in your water.

For example, your filter may contain a sediment filter with a much smaller micron rating than that of the sediments contaminating your water. This can cause clogging issues and the need to replace the filters sooner than under normal circumstances.

If this happens often enough, it may be more practical to size your sediment filter accordingly, that is, to replace your existing sediment filter with one that has a higher micron rating.

Some filters are replaced in full, meaning that the entire filter housing and the filter media contained within it are replaced as well. This is the case with in-line filters, shower filters or fridge filters, which don’t have replaceable inserts.

The number one reason why you should replace your filters is to ensure that your water filter producers contaminant-free drinking water every time you turn on the tap. As mentioned before, with time, the filter media in water filter cartridges becomes saturated with contaminants, which not only  leads to a drop in  water flow, but also to possible drinking water contamination issues.

Overused water filter cartridges can also be a breeding ground for bacteria, which can cause   taste and odour issues, and even some more serious illnesses (severe diarrhoea, gastrointestinal problems, etc.) if they end up in your drinking water.

When should I change my water filter cartridges?

The general rule of thumb for replacing water filter cartridges is to replace them according to the instructions of the manufacturer.  This means respecting water filter replacement deadlines and instructions related to the actual replacement process.

The packaging of water filter cartridges or your water filter system’s user manual will usually have instructions on how often you should replace your filters and how to carry out filter replacement.

Because many factors can influence the service life of a water filter cartridge, the manufacturer’s instructions about how often you should replace your filter cartridges are usually just guidelines. It may be that due to the changes in the quality of your water, water usage and filter quality you may need to replace your filters sooner than expected.

Some water filters systems have filter cartridge health monitoring systems that will alert you when it’s time to replace your filters. For example, some reverse osmosis filters like the BMB-30 Nova Pro Direct Flow 9-stage Reverse Osmosis System or some under sink water filters like the Brita filter systems are fitted with filter health monitoring systems.

If your filter does not have a monitoring system, you need to rely on your water filter manufacturers guidelines, and your own monitoring of any changes in the quality of your drinking water and in the performance of your water filter.

 Here are some of the most common signs that you need to change your filter cartridges:

  • Sudden drop in water pressure;
  • Strange tasting water (e.g. water tastes salty, tastes like metal, etc.);
  • Strange smelling water (e.g. water smells like bleach, rotten eggs, dirt, etc.);
  • Changes in the appearance of your water (e.g. water is cloudy, milky, or tiny particles appear in your water).

Also Read: 3 Signs You Need to Replace Your Water Filter Cartridges

Whenever you replace your filters remember to set a reminder for the next filter replacement date. Alternatively, you can enrol in filter reminder programs when you purchase filters online. These reminder programs will automatically send you an email whenever you need to change your filters. This makes it easy to re-order the same filters and to never forget to change your filters on time.

Multi-stage water filters like reverse osmosis water filters or whole house water filters are equipped with multiple filter cartridges that need changing at different intervals.  For example, in a reverse osmosis system, pre-filters may need to be replaced as often as every six months, but reverse osmosis membranes can last up to 12 or even 18 months.

One of the reasons behind this difference in service life is the function of each filter.  Pre- filters are designed to remove sediments and particulates, and one of their roles is to protect the reverse osmosis membrane from damage and clogging.

How to change water filter cartridges?

Residential water filters are designed with usability in mind, and this extends to both installation and maintenance. When changing filters always closely follow your manufacturer’s instructions.

Not all filters are made equal, but for the most part, water filter replacement can be done without the intervention of a plumber, and many residential water filters use the so called quick-change filter technology, which allows an easy and fast replacement of filters.

The user manual of your water filter system contains detailed descriptions both for the installation and changing of filters. Following these instructions will make sure that you change your filters safely and correctly.

Although, as a general rule, most water filter cartridges are not reusable, there a few exceptions. Some ceramic water filters cartridges, like the ones manufactured by Doulton,  can be reused by cleaning them. Of course, these filters cannot be reused indefinitely either.  You may clean them and reuse them for a limited time only.

Apart from ceramic filters, some pleated filters can also be reused by washing them under running water. These too can only be reused for a limited number of times.

When buying replacement filters, always check that they are compatible with the brand and model of your water filter. Some filters are breakable or can be damaged very easily (e.g. UV bulbs, ceramic filters), so we recommend handling them with care to avoid dropping them or damaging them in any other way.

Store replacement cartridges in their original packaging in a dry and cool place. If your replacement filters show signs of damage or if you accidentally drop easily breakable filters, you mustn’t reuse them as there is a risk of contaminants seeping through any fissures or cracks that resulted from the drop.

Always buy filters replacements from reputable vendors and always double check that the filters you’re about to buy are compatible with your filter system. When in doubt, do not hesitate to contact the customer support team of your vendor.

Dispose of used filters through your vendor’s or manufacturer’s recycling program or through the normal plastic recycling program available in your area. If you’re not sure how to dispose of used filters, get in touch with your vendor.


To avoid system malfunctions, clogging, and compromised water quality, change your filters as instructed by your manufacturer or whenever needed. This will ensure that your filter system filters water to the best of its abilities, without anything to hinder its performance.

If you have problems remembering to change filters, enrol in filter change reminders available at water filter vendors. These programs will send you an email notification about your next scheduled filter change.

If you don’t want to order filters every time you need to change them, you can stock up on replacement filters by buying them in bundles to save money. Either way, overused filters can undermine your efforts to get purified water on tap, so it’s always best to have new filters at hand.


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