Comprehensive Guide: How Do Refrigerator Water Filters Actually Work?

Refrigerator filters are constituted of simple or coconut shell-activated carbon medium. The latter is manufactured from renewable resources and is, thus, eco-friendly. The medium works through adsorption, 0.5-micron pore filtration, and chemical reactions between carbon and water pollutants.

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Have you ever wondered how your refrigerator filter supplies tasty drinking water? Stop wondering and keep reading this article to understand the working of these filters. After consulting various water filter experts, here’s what we came up with.

Refrigerator filters, mostly containing activated carbon, work on three simple principles: Adsorption, minute-level filtration due to 0.5-micron pore size, and chemical reactions with contaminants present in water.


Structure Of Refrigerator Filter (PP shell+activated carbon block)


Refrigerator filters are connected to a tap water pipeline, which flows through the fridge. The filter cartridge housing is made from Polypropylene (PP), whereas the medium is built from activated carbon.

The supplied pressure from the pipeline allows dirty water to penetrate and make its way through the filter. But, thanks to the design of the carbon block medium, only healthy drinking water can reach the central pipe leading to the faucet of the fridge water dispenser.

Most impurities and contaminants are left behind in the medium, making the water clean and safe for human consumption.


Water Flow Direction In Refrigerator Water Filter



How Does A Refrigerator Water Filter Work?

Refrigerator filters are constituted of simple or coconut shell-activated carbon medium. The latter is manufactured from renewable resources and is, thus, eco-friendly. The medium works through adsorption, 0.5-micron pore filtration, and chemical reactions between carbon and water pollutants.

Jacobi, situated in Sri Lanka, is one of the top manufacturers of high-quality activated carbon, such as Samsung, and is used by Glacier Fresh. The products are based on fair and sustainable sourcing of coconuts.



How Do Activated Carbon Filters Work?

The main motive of activated carbon filters is to reduce impurity levels in water and make it safe for drinking. Before we begin, we should know that activated carbon is made from organic materials such as charcoal granules, coconut shells, and wood.

These materials are treated to become extremely porous. They also have a large surface area which makes them effective at reducing bad tastes, odors and other particles in water. Here’s a detailed step-by-step explanation of how activated carbon removes impurities:

  • Particle Filtration

This is the basic filtration stage wherein large contaminants such as sediments, debris, sand, silt, and fibers are filtered.

  • Physical Adsorption

Adsorption is a surface phenomenon that attracts passing contaminants, polar compounds, to permanently stick on the surface of carbon particles. The effectiveness of bonding depends on the temperature and flow of water. Ideally, smaller active carbon filters should be supplied with cold water at low pressure.

The scanning electron microscopy (SEM) image of activated carbon (a) before and (b) after the uptake process

  • Massive Surface

The infinite number of small carbon particles leads to a massive total surface area. For example, just 4 grams of activated carbon medium has a surface area equivalent to 6400 sqm, which is the size of a football field. The more the surface, the more space is available for contaminants to adhere.

  • 0.5 μm Pore Size

The carbon particles are so closely packed in such filters that their average pore size is just 0.5 μm. It allows the water to maintain all minute valuable minerals while harmful pollutants and solids stay behind.

  • Chemical Adsorption

Sometimes, chemical reactions are also responsible for removing pollutants in carbon filters, such as reduction, catalytic decomposition, and formation of coordinate compounds. Here’s an example of chlorine:

Reduction: C* + NH2Cl + H20 → NH3 + H+ + Cl- + CO

Catalytic Decomposition: CO + 2NH2Cl → C* + 2H+ + 2Cl- + H20 + N2


What Gets Filtered?

Refrigerator filters containing activated carbon-block filter mediums are designed to hold back several contaminants and provide healthy drinking water. Thus, it efficiently brings down impurity content well under safe limits.

What Substances Are Contained In Tap Water?

Tap water contains hundreds of substances. It includes minerals, chlorine, heavy metals, their salts (nitrates, phosphates, carbonates, sulfates), microorganisms (bacteria, viruses, cysts), chemicals, organic matter, and dirt. While some might be safe and essential for your health, other impurities are harmful.

What Do Refrigerator Filters Remove?

According to NSF and EPA studies, activated carbon in refrigerator filters can remove up to 80 chemicals, reduce levels of 30, and be moderately good at reducing 22 more. They are recommended to eliminate 32 organic compounds, 14 pesticides, and 12 common herbicides.

efrigerator filters can eliminate chlorine, chlorine bi-products, chlorides, pesticides, herbicides, nitrates, PFAS (Per- or Polyfluoroalkyl substances), phosphates, lithium, pharmaceuticals, microplastics, and some bacteria. High-grade or special activated carbon filters can also remove heavy metals, limescale, fluoride, and more microbiological contaminants.

Activated carbon is most efficient at removing chlorine apart from other impurities. That’s great news because drinking water containing chlorine is bad for your health in the long term. Moreover, it imparts an unpleasant taste and odor to your water.

You should also check the NSF certification provided to the water filters as it justifies their ability to remove certain contaminants. Filters that have passed different certification standards can remove different harmful substances. Here are some of them:

  • NSF-42 certified filters can remove aesthetic impurities, including chlorine, and remove bad taste or odor.
  • NSF-53 certified filters can remove or reduce all inorganic and organic harmful contaminants that cause adverse health effects, including chlorine.
  • NSF-401 certified filters can remove or reduce about 15 emerging impurities like pharmaceuticals, detergents, pesticides, herbicides, and flame retardants such as chlorine and its byproducts.


How Do Refrigerator Water Filters Change Your Life?

Refrigerator water filters are a life-saver as they are energy, cost, time, and space efficient. They solve the purpose of providing clean, healthy water for you and your family without taking up much space in the house. Refrigerator filters can purify thousands of gallons of water in their lifetime with good speed and consistency.

You must know that a refrigerator filter costs less than 20$ and lasts longer than bottled water, whose cost can go over 100$. It can provide clean water for over 4 - 6 months, depending on your usage, which is light on your budget.

A very important feature of refrigerator filters is that they are eco-friendly. Using such filters discards the need to use plastic bottles. Additionally, you don’t have to waste time or energy chilling your filtered water in the fridge as the filter already takes care of that before dispensing water.

The procedure of extracting clean water is also very convenient in refrigerator filters. You just have to keep your glass at the water dispenser, and ice-cold drinking water comes pouring down in no time at any time of the day throughout the year.

Once the lifespan of your refrigerator filter is over, you will be indicated by smart lights or clear signs like dirty, smelly, tinted, or slow water. Buy a new budget-friendly filter, replace it yourself or hire a professional. So, you will have a new filter at your service for the next few months.

Why Do You Need To Change Your Refrigerator Water Filter?

Every filter needs replacement after a certain period due to wear and tear or blockage. Similarly, refrigerator water filters consisting of an activated carbon block medium with countless particles and 0.5 μm pore size has a saturation limit. Its massive surface area adsorbs harmful dissolved particles present in water on its surface like a sponge soaks up water. After filtering water continuously for months, the filter fills up with contaminants and needs to be changed. Remember that the longer you delay replacement, the longer you will drink unhealthy water.

What Happens If You Don't Change Your Fridge Water Filter?

If you do not change your refrigerator filter even after the recommended period, you are taking a risk. Activated carbon block filters have crushed carbon pieces in granular or block form to shape a porous medium.

Unfortunately, these pores are limited, and once they are blocked because of filtering dirty water for a long time, the filter stops functioning. Plus, the saturated medium becomes a perfect place to breed bacteria. So you have to replace it with a new one; otherwise, the outcoming water will be no better than untreated tap water.

Why Is My Refrigerator's Water Dispenser So Slow?

If your refrigerator’s water dispenser is discharging water slowly, it is probably a sign that your filter needs replacement. When your filter has clogged pores due to contaminant build-up, space for the passing of water reduces. So, change your filter to restore the speed of flow.



Now that you have reached the end of this article, I hope you have understood how refrigerator filters work. You must also know what contaminants are removed by these filters and the signs of their need for replacement at the right time.

Instead of buying expensive replacement filters made by original manufacturers, buy a pocket-friendly filter that can do the job equally well. Go for a filter that can remove more contaminants before they enter the fridge.

Overall, the filtration capacity of activated carbon filters is based on their build. The carbon surface forms bonds with substances present in water, leaving the water free from contaminants. However, they do not filter out every element from water, so ensure that your requirements are fulfilled. Have a good water day!


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