How do Water Filters Work?

Water filters work by removing contaminants in the water in different stages as it passes through. In the first stage, larger particles like sediment are removed. In the next stage, activated carbon acts like a magnet for chemicals like chlorine, heavy metals like lead, and volatile organic compounds like fossil fuels. Finally, a very fine grade of filter targets bacteria and other microorganisms.

One advantage we have when it comes to filtering water is that water molecules are very small, made up of just 3 atoms: two hydrogen and one oxygen, which is smaller than viruses and much smaller than bacteria and most contaminants. Because of that we can send the water through screens which will cause the larger particles and most microorganisms to get trapped and left behind. One issue with that is, if we just sent all of our water straight into a very fine grade of filter, it would quickly clog up and become useless. So instead, we start out with a larger grade of filter and slowly reduce it down until we’re as close as possible to only allowing water molecules to pass through. If we also make our screens out of different materials, we can take advantage of ion charges and other chemical reactions to cause undesirable particles to stick to them and get left behind.

How Often Should I Replace Water Filters?

Filter cartridges do their work filtering out sediments and any contaminants that exist in drinking water, but over time those cartridges will naturally become less effective as particles build up on their surfaces. Changing your water filter cartridges on a regular basis will ensure safe, great-tasting water keeps flowing for your family.

Manufacturers may vary a little in how often filter cartridges should be replaced but the table here is a general guideline based on a family of 4 and the average person requiring around 4 litres per day. Obviously smaller families would need to replace filters less frequently while larger families would need to do that more frequently.

Average for a family of four

More frequent replacement may also be required if you notice reduced water pressure or no water flow, if the water becomes discoloured or you can see particles in it, or if the taste or smell has deteriorated. Failure to replace filter cartridges at the recommended intervals may not only result in bacteria growth affecting water quality, it can damage a powered water filter system if the pump gets overloaded trying to push water through blocked filters.

What is a 3-stage water filter and how does it compare to a single stage filter?

When looking at purchasing and installing a water filtration system for the home you may be surprised by the variety of water filtration systems available in the market. One decision can be whether to choose a single stage or a multi-stage system.

Single stage water filtration systems usually use a carbon-based filter cartridge which contains various combinations of activated carbon. Activated carbon is one of the best filter media for improving tap water’s taste or smell. However, tap and tank water sometimes can sometimes contain sediment or other contaminants which a carbon filter may not be efficient in removing, or may become blocked in an unusually short time.

Usually, a sediment filter is required to remove larger particles in the water. The sediment in the water can cause the appearance of tap water to change, becoming cloudy or acquiring a brown-reddish colour. The sediment can come from infrastructure issues or household plumbing, or perhaps rust or dirt washed from the roof and ending up in rain water tanks. Extreme weather events such as droughts and floods are another common cause.  Therefore, including a sediment filter in addition to a carbon filter will be more efficient than a single stage carbon filter. Sediment filters are usually available in various grades to remove particles from 1 micron up to 50 microns.

In addition to sediment and carbon filters, in EZEK 3-stage water filtration systems, a third stage is added which has a very fine grade of filter called EM-Medium. These target microorganisms and other pathogens.

Some water filter products combine multiple stages into a single cartridge but this usually means that if one stage gets blocked, a new filter cartridge is required.

With a multi-stage filter system which has separate cartridges for each stage, it becomes more cost effective to replace each stage as required.  For example, if the sediment filter becomes clogged due to dirty water, you will only need to replace this cartridge, and the other cartridges will still be fine for some time.

The Alya water jug filter is silver Impregnated Coconut Activated Carbon and Sodium-free Cation Exchange Resin.  It can remove larger particles as well as chlorine, pesticides and heavy metals for better tasting and safer water.
Other products such as the 3 stage under sink and above sink water filters include 3 cartridges to provide clean and healthy drinking water

The diagram below shows the 3 stages used in EZEK benchtop and under-sink water filtration systems. In the first stage, tap water goes through a polypropylene or PP filter to remove any larger particles like dirt and rust. The second stage is a finer grade granular activated carbon filter which is constructed by heating coconut shells to turn them to carbon and then crushing them into granules. These target chlorine and other chemicals including heavy metals and volatile organic compounds. The final EM-Medium stage is a very fine grade of filter which targets microorganisms and other pathogens. EM-Medium is a NASA technology used for the recycling of water in space programs.

Watch the video below for more detailed information on the 3 stage EZEK water filtration systems which includes a description of the function of each filter cartridge.