How Countertop Filters Work

Countertop filters are compact, simple systems that purify water and remove contaminants. These systems are ideal as an impermanent, no-commitment filtration solution with no installation required.

But the size and simplicity of these devices can make people doubt their efficacy. In reality, countertop filters are highly effective at removing common water contaminants. Here’s how they do it.

How a Countertop Filter Works – The External Aspect

A countertop filter is easy to install and doesn’t require any plumbing. This ease of installation and usage is what makes the countertop filter portable and versatile.

How countertop filter works

How to install the Homemaster TMJRF2.

Simply replace your faucet’s aerator with the diverter tab of the filter. That’s the only installation that needs to be done.

When you turn on your kitchen faucet and pull the small diverter tab at the end of the faucet, the spout of the countertop filter should dispense filtered water.

By pulling the tab, you’re shutting off the faucet and diverting water into the filter through the filter hose. The water runs through the stages of filtration before coming out the spout.

Once you’ve filled your glass, simply turn off your faucet as per normal. The diverter tab will fall back into place and the kitchen faucet will work as usual.

How a Countertop Filter Works – The Internal Aspect

Countertop filters typically use a multi-stage process to filter water, using several filtration mediums to remove impurities from water.

Each filtration medium is suited to remove only certain types of contaminants, so a system that utilizes several mediums has a greater chance of removing more contaminants from the water. No single filter type is able to remove 100% of contaminants from water. Even distillation, considered the purest type of water, can let volatile organic compounds (VOCs) through.

Countertop filter system explanation

A multi-stage countertop filter. This is the APEX 5-Stage Model.

The most common filtration mediums used in countertop filters are as follows:

1- Carbon Filter

Carbon filtration is one of the most popular and commonly used methods to filter water. There are two main types of carbon filters – activated carbon block (ACB) and granulated activated carbon (GAC).

  • Activated Carbon Block – ACB is more effective and has an extremely high adsorption capacity. It’s made of carbon powder, which gives it more surface area to trap contaminants. However, ACB filters have slower filtration rates due to the compressed nature of the carbon.
  • Granular Activated Carbon – GAC is made of loose carbon pellets fit into the filter housing. It works on the same principle as ACB, but water flows faster through GAC and the shorter contact time between water and filter means more contaminants get through.

Carbon filtration can remove up to 98% of chlorine from water, so if chlorine is your biggest issue, look for a countertop filter with GAC or ideally, ACB.

2- Reverse Osmosis

Some countertop filters use Reverse Osmosis, which is an intense filtration system that removes most of the contaminants in water. It does this by forcing the water through a semi-permeable membrane.

As the water squeezes through, the contaminants are left behind and thrown away as wastewater. RO is an excellent option, producing demineralized water, but it may let some microorganisms and certain contaminants through.

3- KDF Filtration

KDF stands for Kinetic Degradation Fluxion and contain a granular zinc alloy that creates an electrochemical reaction when it encounters chemicals like chlorine.

During this reaction, the structures of some harmful chemicals like chlorine are changed and made harmless. Others, like copper and mercury are removed altogether from the water, effectively freeing the water of these contaminants. KDF also removes foul smells and taste from the water.

KDF is best used in conjunction with other types of filters, particularly carbon filters. However, it is expensive as this is a patented filtration medium.

4- Alkalization

Some countertop filters include an alkalization stage, where the water is subjected to infrared rays which ionize the water and reduces its acidity. Alkaline water can be beneficial for health, but it also makes the water taste good.

The Bottom Line

Overall, countertop filters are the best choice if you want clean, uncontaminated water for your family with minimal investment and effort. These handy, portable and highly effective filters are perfect for any home, office or to take travelling.

Hopefully this guide has cleared up any doubts you may have had about how countertop filters work.  

Learn more about the best countertop filters here. 

You can also compare countertop filters vs. under-sink filters vs. faucet filters in our detailed guide. 

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