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Get To Know The Filter Cartridges In Your Water Filtration System

Get To Know The Filter Cartridges In Your Water Filtration System

So, what does having the best whole house water filter cartridge for your filtration system mean? Or why does your Brita water purifier insist on coconut-based activated carbon resin filters?

Wouldn’t it be nice to understand how these filter cartridges work and how vital they are to ensuring freshwater flowing through your home? Because let’s face it, poorly made filters that wear out quickly will inadequately filter your water, cost you more money, and will not handle the demand in your home.

Problems you may be experiencing with your filtration unit are often the result of cartridge issues. But if you do suspect it may be time to replace your water filtration system, quality filter cartridges should be one of the key deciding factors for your next purchase. After reading this article, you can check these cartridges out for your whole house water filter.

The Wide World Of Water Filter Cartridges

Forget attractive casings, nickel-plated chrome fixtures, and silicon tubing. The filter cartridge really is the heart of any filtration system. Each brand varies in the efficiency, quality of materials, disposal methods and waste ratio.

Cleverly-written marketing copy can’t compensate for a filter cartridge that underperforms. As you read reviews of the best water dispensers, look for details and specs regarding the cartridges. Any filtration system that doesn’t offer a wealth of detail about the filters used is either hiding something, or just really bad at marketing.

Pay special attention to the following:

  1. EPA Approval Rating: Indicates the filter cartridge meets the standards approved by the EPA for proper, safe water treatment
  2. Micron Rating: Indicates the pore size of the filter surface, and its efficiency at removing particles measured in microns. Get the right micron rating for the job.
  3. List of Contaminants Treated Or Removed: After testing your tap water, read the list of contaminants treated by your water filter carefully to makes sure invest in the right one. A sediment filter can remove dust, undissolved metals and sand particles, but not bacteria, for instance.

Microns Make the Difference

When it comes to judging the quality of a water filter cartridge, it all comes down to microns. A micron is a microscopic unit of measurement applied to objects too small for the human eye to see. The average legionella virus that might be lurking in a well water source is only 0.005 – 0.3 microns in size. For context, the average human hair is 70 microns.

Micron Comparison Table

Micron Size
0.005 – 0.3
90% Of All Contaminants
0.5 – 2.0
Lead Dust
Household Dust
Human Hair
Sand (Beach)
100 – 2000

That being said, removing tiny ion particles or harmful pathogens means trapping them in passages too small for them to pass through. Water filters used for removing sediment, TDS’s, and certain chemicals will typically feature filter cartridges made of porous, highly durable, synthetic material. As the dirty water is forced through the filter, the harmful elements remain trapped in the cartridge, while the clean, uncontaminated H20 molecules can pass through the filter easily.

You’ll find most brands of water filtration systems offer their own line of special filter cartridges. The smaller the micron, the more effective the filter. It also means that frequent washing or even replacement may be necessary, adding to the cost of maintenance.

Industry Ratings For Filter Cartridges

Despite any claims by a manufacturer, the frequency with which you change filter cartridges is impacted by several factors. Depending on the level of contamination, flow rate of your water, and demand.

The Environmental Protection Agency is a national government body that regulates eco-friendly standards and policies for manufacturers and industries across. Manufacturers of filter cartridges are required to meet EPA standards for the use, handling and safe disposal of your filter cartridge.

NMR Ratings
Filter cartridges designated ‘NMR, or nominal micron rating indicates that the filter will capture most but not all of the contaminants in your water. Your filter’s NMR rate might be 95% at 8 microns, for example. indicating that the filter can capture 95% of any contaminants 8 microns or smaller.

AMR Ratings
An Absolute Micron Rating, or AMR, is measured in a slightly different manner than a NMR rated filter. Tiny glass beads are poured through the filter in one pass. The remaining beads are counted to provide a rating calculated as a percentage. In other words, if 100 beads were poured through an active alumina filter and only 10 remained, the AMR rating would be 90%.

Different Types of Filter Cartridges

Different Types of Filter Cartridges

1. Activated Carbon Filter
An Activated carbon filter, also called activated charcoal, is a type of compressed carbon, manufactured by a process that produces small, low-volume pores. These tiny pores can drastically increase the surface area available for adsorption or chemical reactions.

You’ll sometimes see the word ‘Activated’ substituted for active but it means the same thing. They’re most popular in water softeners because they are so effective at removing manganese and calcium ions.

Countertop water filters and water purifiers for dispensing cold water often include an active carbon filter, which is also highly effective at removing chlorine. Since chlorine was the primary method of water treatment for many city water supplies, it’s not uncommon to taste or smell chlorine in tap water.

In certain cases, an active carbon filter can be used to remove VOC’s (volatile active chemicals). Not to worry, though, they’re completely safe to use and won’t leach chemicals back into your treated water.

Certain brands of activated carbon filter can be recycled. Many can be washed and reused to extend the life of the filter. A non-hazardous, spent carbon filter can be disposed of without any harm to the environment or your health.

  • Widely used in residential water treatment
  • Cannot remove sediment, minerals, or dissolved inorganic compounds
  • Easy to replace (recyclable, washable)
  • Effective at removing VOC’s, chlorine, and improving water taste

2. Activated Alumina Water Filter
Manufactured from aluminum hydroxide, activated alumina is actually the same substance as ruby or sapphire, absent of color impurities. In the manufacturing process, it’s treated in such a way as to make it more porous. With its porous surface area of over 200 m²/g, you’ll find it used as a filter for removing fluoride, selenium and arsenic in drinking water.

Water filtration systems that feature an activated alumina filter can effectively remove up to 99% of fluoride. It’s completely safe to handle and poses no danger to humans or animals, but aluminum oxide can cause mild skin irritation.

Due to its highly porous surface area, activated alumina filters are also used as a desiccant to absorb water. Tiny water vapors and droplets, however, can get trapped inside the microscopic pores, rendering the filter less effective.

Safe To Use
A common misconception is that activated alumina adds aluminum or leaks aluminum into your water, making it potentially harmful. This is completely false [1]. Activated Alumina is certified by the NSA, which has approved its use for industrial and commercial purposes.

Replacement And Disposal
Activated alumina filters are washable and disposable. Repeated washes can extend the life of your filter for a while. Over time, though, the added wear and tear can degrade the quality and effectiveness by widening the surface pores. It’s always best to follow the directions for replacement as outlined by the manufacturer. According to the EPA, the procedure for safely disposing of liquid residual is:

“The most common methods for liquid residual disposal is discharge to a sewer. Some water systems may also be able to dispose of liquid residuals by direct discharge to a water body, in underground injection wells, in on-site wastewater treatment systems, or hauling the liquid residuals to a wastewater treatment plant. If liquid residual disposal options are limited or unavailable, there are treatment units that do not generate significant quantities of liquid waste [2].”

  • Removes arsenic, thallium, selenium and fluoride
  • May need frequent replacing if treating high levels of contamination
  • Highly porous surface area
  • Needs to be disposed of properly due to residue
  • Can be regenerated for multiple uses

3. Granulated Activated Carbon Filter
Also referred to as a GAC filter, a granulated carbon filter is made of highly porous adsorbent material. It’s produced by heating carbon-rich organic matter (wood, coal, coconut shell) in a vacuum. Then the material is crushed into fine granules.

The most common use for GAC filters is for the removal of chemicals that produce an objectionable odor or taste. Hydrogen sulfide and chlorine can leave behind a strong odor or taste, but a GAC filter is designed to absorb these molecules.

A GAC filter can also be effective at the removal of VOC’s, but is not harmful to handle. If you notice the distinct carbon smell is gone from the filters, it’s time to replace the cartridges. On average, a quality GAC filter should last 2 years with daily use, under ideal conditions. Its durability will largely depend on the level of contamination and your level of use.

The best brand of activated carbon and granulated active carbon filters can be regenerated to extend the life of the filter.

  • Removes bad odors (hydrogen sulfide) and excessive chlorine from water
  • Cartridge replacement can be costly
  • Lasts up to 24 months with daily use and regeneration
  • Does not remove bacteria, sediment, or undissolved chemicals
  • Can be safely disposed of

4. Reverse Osmosis Filters
Commonly found in whole house water filtration systems, an RO filtration media or reverse osmosis membrane is designed to remove ions, particle residue and undesirable molecules from your drinking water.

An RO filtration media is very thick and serves as a filtration bed for removing larger particles.
An RO membrane is partially permeable and much thinner, for filtering out pollutants.

Reverse osmosis filters are quite popular because they can effectively treat a wide range of contaminants with up to 99% efficiency [4].

  • Metal Ions
  • Aqueous Salts
  • Sodium, chloride, copper, chromium, and lead
  • Arsenic, Fluoride, Radium, Sulfate, Calcium, Magnesium,
  • Potassium, Nitrate, and Phosphorous.
    protozoa (eg Cryptosporidium, Giardia)
  • Bacteria (eg Campylobacter, Salmonella, Shigella, E. coli)
  • Viruses (eg Enteric, Hepatitis A, Norovirus, Rotavirus)

Backflushing is the preferred method of regenerating your reverse osmosis filter. Generally speaking though, a quality RO filter, membrane or filtration media will last between 2 – 5 years with proper care. Always read the manufacturer’s instructions for the safe disposal of your RO filter cartridge.

Removes a wide range of chemicals, bacteria and virusesProduces higher waste ratio than other types of filters
Diverse application Can be costly to maintain and replace

Cannot remove dissolved gases (eg hydrogen sulfide)


Improving the taste, health and quality of your drinking water at home is an important decision. With a deeper understanding of the different types of filter cartridges, you’ll be better informed when you’re ready to choose a water filtration system. Once you’ve tested your tap water and you know which pollutants need to be removed, seek out a filter that’s appropriate.

Pay close attention to the filter specifications when reading online reviews, especially the micron size and rating. Over time, the cost of replacing filter cartridges can impact your household budget. Look for high grade materials and recyclable filters that can be regenerated for extended use. Take care of your filter cartridges, and they’ll take care of you!


[1] 10 False Statements About Water Filters (Better Business Bureau)

[2] Radionuclides In Drinking Water; Disposal Issues (EPA)

[3] A Guide to Drinking Water Treatment Technologies for Household Use (Centers For Disease Control And Prevention)

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