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A Helpful Guide to Water Filters

"If you're unsure of your water's quality, get it tested. We recommend testing your water to assess the specific contaminants present in your water. This can help determine the appropriate micron rating and other filtration requirements for your drinking water needs.

What is Carbon Water Filtration?

Most carbon water filters are made by grinding up coconut shells and then superheating them to remove impurities. Using hot steam to open up pores in the carbon increases the surface area to which other chemicals can bond.

Carbon has the ability to bond to different compounds and then form long carbon chains, making it effective at trapping unwanted chemicals.

Activated carbon filters use a process called adsorption to filter out unwanted compounds from your water. Adsorption is when a solid substance attracts other molecules to its surface. Carbon bonds easily and strongly to other chemicals. A good way to describe it is that it acts like a magnet for unwanted compounds in the water, a process called chemical adsorption.

Carbon filters use chemical and physical adsorption. Neutral molecules in water stick to each other through weak electric forces. Carbon has a strong attraction that pulls out non-water molecules.

Benefits of Carbon Activated Filters

A carbon-activated filter, also known as activated carbon or activated charcoal filter, is a type of water filtration system that uses a porous carbon material to remove impurities from water. The activated carbon has a large surface area with numerous tiny pores, which helps trap and absorb contaminants.

Here's how a carbon-activated filter works:

Adsorption: The porous structure of activated carbon provides a large surface area for contaminants to adhere to. As water passes through the filter, organic compounds, chlorine, volatile organic compounds (VOCs), and some heavy metals are attracted to the surface of the carbon and become attached to it through a process called adsorption. This effectively reduces their concentration in the water.

Chemical Filtration: Activated carbon filters can also chemically react with certain contaminants, neutralizing them or converting them into less harmful forms. For example, activated carbon can remove chlorine and chloramines from water by chemically bonding with them.

Taste and Odor Improvement: Carbon-activated filters can significantly improve the taste and odor of water by removing unpleasant substances that contribute to these issues. This includes compounds like hydrogen sulfide, certain volatile organic compounds, and residual chlorine.

What Does an Activated Carbon Filter Remove?

Chlorine and Chloramine: Activated carbon can effectively remove chlorine and chloramine, which are commonly used in water treatment to disinfect water supplies. Removing these chemicals can improve the taste and odor of water.

Volatile Organic Compounds (VOCs): VOCs are organic chemicals that can evaporate and be present in the air or water. Activated carbon filters can adsorb many VOCs, including benzene, toluene, and xylene.

Taste and Odor Compounds: Activated carbon can help eliminate unpleasant tastes and odors caused by organic compounds in water.

Some Pesticides and Herbicides: Activated carbon can adsorb certain pesticides and herbicides, although its effectiveness can vary depending on the specific compounds involved.

Some Pharmaceuticals and Endocrine Disruptors: Certain pharmaceutical compounds and endocrine-disrupting chemicals can be removed by activated carbon filtration.

Some Heavy Metals: Activated carbon may have some limited ability to remove certain heavy metals, such as lead and mercury, but it is not as efficient as other specialized filtration methods like reverse osmosis.

What Activated Carbon Filters Don't Remove

However, it's essential to note that activated carbon filters have limitations and may not effectively remove all contaminants. For instance, they are not efficient in removing nitrates, dissolved minerals, or microorganisms. To ensure the removal of specific contaminants, it is advisable to use appropriate filtration technologies tailored to the water quality issues in question. Water testing can help determine the best filtration approach for your specific needs.

To remove nitrates from water, specialized methods like ion exchange, reverse osmosis, or distillation are typically used. These processes can effectively reduce nitrate levels and ensure safe drinking water. If you suspect your water contains elevated nitrate levels, it is essential to use appropriate water treatment methods to address the issue. It's also advisable to have your water tested to determine the nitrate concentration accurately before selecting the appropriate treatment method.

According to the EPA, carbon filters effectively remove the 14 most common pesticides, the 12 most common herbicides, and all 32 identified organic contaminants, including potentially cancerous compounds like chlorine byproducts.

What Are Volatile Organic Compounds?

Volatile Organic Compounds (VOCs) can also be found in water, although they are typically present at lower concentrations compared to their presence in the air. VOCs can enter water sources through various means, such as industrial discharges, runoff from agricultural activities, and contamination from underground storage tanks or landfills. Here are some examples of VOCs that can be found in water:

Industrial Chemicals: Chemicals used in industrial processes, such as benzene, toluene, ethylbenzene, and xylene (BTEX), can contaminate water sources. These compounds are commonly associated with petroleum refining, chemical manufacturing, and other industrial activities.

Solvents: Solvents like trichloroethylene (TCE), perchloroethylene (PCE), and methylene chloride can be released into water sources through improper disposal or industrial practices. These compounds are often used in dry cleaning, metal degreasing, and as paint strippers.

Pesticides: Certain pesticides, including herbicides, insecticides, and fungicides, can be detected in water supplies. Examples include atrazine, glyphosate, and chlorpyrifos.

Fuel Components: Fuel-related compounds, such as gasoline additives like methyl tert-butyl ether (MTBE), can contaminate water sources through leaking underground storage tanks or spills.

The presence of VOCs in water can pose health risks, depending on the specific compounds and their concentrations. Ingesting water contaminated with high levels of certain VOCs over a prolonged period may lead to adverse health effects, including damage to the liver, kidneys, or central nervous system, as well as an increased risk of certain types of cancer.

Benefits of KDF Water Filter

KDF (Kinetic Degradation Fluxion) is a type of water filtration media that is often used in combination with other filtration technologies to improve water quality. KDF media consists of a blend of copper and zinc in a specific ratio and is designed to target specific contaminants through various chemical and electrochemical processes. KDF is commonly used in water filters, shower filters, and other water treatment systems. Here's how KDF works and what it does in a filter:

  1. Chlorine and Chloramines Removal: KDF is effective at removing chlorine and chloramines from water. These chemicals are often added to municipal water supplies for disinfection, but they can cause an unpleasant taste and odor in water. KDF reacts with chlorine and chloramines, converting them into less harmful forms that are less likely to affect the water's taste and smell.

  2. Heavy Metal Reduction: KDF can target certain heavy metals, including lead, mercury, copper, and others, by facilitating redox reactions that convert these metals into less soluble and less harmful forms. The copper and zinc in KDF act as catalysts for these reactions.

  3. Scale and Microbial Growth Prevention: KDF has properties that can help prevent the buildup of scale (calcium and magnesium deposits) in pipes and appliances by inhibiting their crystallization. Additionally, KDF's antimicrobial properties can help reduce the growth of bacteria and algae in the water.

  4. Hydrogen Sulfide Removal: KDF can also address the issue of hydrogen sulfide (the "rotten egg" smell) in water by converting it into a non-odorous form.

  5. pH Stabilization: KDF can help stabilize the pH of water by acting as a pH buffer, which can be beneficial in ensuring that the water remains within a certain pH range.

Carbon Block vs Granulated Carbon Filters

Granulated activated carbon (GAC) filters and carbon block filters are two common types of activated carbon-based water filtration systems. They both use activated carbon to remove impurities from water, but they differ in their structure, filtration mechanisms, and overall effectiveness. Here's a breakdown of the differences between the two:

Granulated Activated Carbon (GAC) Filter:

  1. Structure: GAC filters consist of loose granules of activated carbon that are typically held in a cartridge or container. The granules vary in size and can be irregular in shape.

  2. Filtration Mechanism: GAC filters work primarily through adsorption, where contaminants in the water adhere to the surface of the carbon granules. The larger surface area provided by the granules allows for effective adsorption of a wide range of impurities, including chlorine, volatile organic compounds (VOCs), and some heavy metals.

  3. Flow Rate: GAC filters can offer a relatively high flow rate due to the loose arrangement of granules, which allows water to pass through more easily. However, this might affect the contact time between water and carbon, potentially impacting the thoroughness of filtration.

Carbon Block Filter:

  1. Structure: Carbon block filters consist of compressed blocks of activated carbon that are densely packed into a solid structure. The carbon is typically finely ground and bonded together with a binding agent.

  2. Filtration Mechanism: Carbon block filters also utilize adsorption for contaminant removal, but the finer structure and denser arrangement of the carbon in a block filter often lead to a higher level of adsorption efficiency. Additionally, carbon block filters often incorporate other filtration media and technologies, such as mechanical filtration and sediment removal, enhancing their overall effectiveness.

  3. Flow Rate: Carbon block filters generally have a lower flow rate compared to GAC filters due to the denser structure. This slower flow allows for better contact time between water and the carbon, resulting in more effective contaminant removal.

Key Differences and Considerations:

  • Effectiveness: Carbon block filters are often considered more effective at removing a wider range of contaminants due to their denser structure and incorporation of multiple filtration mechanisms. They can effectively remove chlorine, heavy metals, sediment, and other impurities.

  • Flow Rate vs. Filtration: GAC filters may have a higher flow rate, but this can come at the cost of thorough filtration. Carbon block filters provide better filtration quality due to their slower flow rate and enhanced contact time.

  • Space and Installation: GAC filters might be more suitable for larger systems due to their higher flow rates, while carbon block filters are commonly used in smaller point-of-use systems like under-sink filters.

When choosing between a granulated activated carbon filter and a carbon block filter, consider your specific water quality needs, the types of contaminants you want to remove, and the available space and installation options. It's advisable to review product specifications and consider third-party certifications to ensure that the chosen filter meets your requirements.

Understanding Micron Ratings

Micron ratings in water filters refer to the size of particles that a filter can effectively remove from water. A micron (μm) is a unit of measurement that represents one millionth of a meter, and it is commonly used to describe the size of particles in water and other fluids. In the context of water filters, the micron rating indicates the minimum size of particles that the filter can capture and remove.

Here's how micron ratings work in water filters:

  1. Particle Size: Water contains various sizes of particles, including sediment, debris, bacteria, algae, and other contaminants. Micron ratings specify the size of particles that the filter can effectively capture. For example, a filter with a 1-micron rating can capture particles as small as 1 micron in diameter.

  2. Filtration Mechanism: Water filters use different mechanisms to capture particles based on their size. Larger particles are typically captured through physical processes like sedimentation and mechanical straining. Smaller particles, including bacteria and other microorganisms, may be captured through adsorption, chemical reactions, or by using filters with very small pores.

  3. Filter Types and Micron Ratings: Different types of water filters have varying micron ratings, depending on their intended use and the types of contaminants they are designed to remove. Here are some common filter types and their associated micron ratings:

    • Sediment Filters: These filters are designed to remove larger particles like sand, silt, and debris. They typically have micron ratings between 1 and 100 microns.

    • Activated Carbon Filters: These filters are effective at removing smaller particles, as well as chemicals and some organic compounds. Their micron ratings can range from 0.5 to 50 microns.

    • Microfiltration Filters: These filters are specifically designed to remove bacteria, protozoa, and some viruses. Their micron ratings are often in the range of 0.1 to 1 micron.

    • Ultrafiltration and Nanofiltration Filters: These advanced filters can remove even smaller particles, including viruses and some dissolved salts. Their micron ratings can be as low as 0.001 microns.

  4. Filter Efficiency: A filter's efficiency depends not only on its micron rating but also on its design, materials, and overall quality. Filters with smaller micron ratings can generally capture a wider range of contaminants, but they might clog more quickly, reducing water flow.

  5. Choosing the Right Filter: The appropriate micron rating for your water filter depends on the quality of your water source and the specific contaminants you want to remove. If you're dealing with fine sediment, bacteria, and other microorganisms, you would need a filter with a smaller micron rating. If you're primarily concerned about larger particles, a higher micron rating may suffice.

It's important to note that while micron ratings provide a general indication of a filter's capabilities, other factors like filter material, flow rate, and maintenance requirements also play crucial roles in determining a filter's overall effectiveness.

Micron size examples

Here are some examples of common objects and particles with their corresponding sizes in microns (μm):

  • Human Hair: About 70 to 100 microns in diameter.
  • Red Blood Cell: Approximately 6 to 8 microns in diameter.
  • White Blood Cell: Around 8 to 20 microns in diameter.
  • Pollen: Typically ranges from 10 to 100 microns in diameter.
  • Dust Particle: Varies, but can be around 2 to 10 microns in diameter.
  • Bacteria: Can vary widely, but many bacteria range from 0.2 to 10 microns in size.
  • Protozoa: Generally in the range of 5 to 50 microns.
  • Virus: Varies greatly, but most viruses are smaller than 0.3 microns, with many being around 0.02 to 0.3 microns.

How long does a water filter last?

The frequency of changing your water filter depends on the type of filter, the quality of your water source, and the manufacturer's recommendations. Here are some general guidelines for when to change different types of water filters:

  1. Sediment Filters: These filters are often used to remove larger particles like sand, silt, and debris. They might need replacement when you notice reduced water flow or pressure due to clogging. As a rough estimate, changing them every 3 to 6 months is common, but it can vary depending on the level of sediment in your water.

  2. Activated Carbon Filters: These filters remove chemicals, chlorine, odors, and some organic compounds. Replace them every 6 months to a year, depending on the manufacturer's recommendation and the volume of water you're filtering.

  3. Microfiltration and Ultrafiltration Filters: These filters are used for removing bacteria and other microorganisms. Typically, you might need to replace them every 6 to 12 months, but the frequency can vary based on water quality and usage.

  4. Reverse Osmosis (RO) Filters: RO systems include multiple stages of filtration. Sediment and carbon filters in an RO system usually need replacement every 3, 6 to 12 months, while the RO membrane might last 2 to 3 years before needing replacement.

  5. UV Filters: Ultraviolet (UV) filters use UV light to disinfect water by inactivating microorganisms. These filters usually have a lamp that needs replacement every 12 months, even if it appears to be working, as the UV intensity diminishes over time.

  6. Whole House Filters: These filters treat water for the entire home. The replacement frequency can vary widely based on the filter type and water quality. Some may need replacement every 6 to 12 months.

Remember that these are general recommendations, and you should always refer to the manufacturer's guidelines for your specific filter. Additionally, factors such as the level of water contamination, usage volume, and local water conditions can influence the replacement schedule. If you notice a significant drop in water flow, unusual taste or odor, or if you're uncertain about the quality of your water, it's a good idea to check and possibly replace the filter sooner. Regular maintenance and replacement of filters are essential to ensure that your water filtration system continues to provide clean and safe water.

What filters should I choose for my home?

Choose from NZ Pump and Water Filters certified safe drinking water filters.

Here are some filters that will reduce the nasty chemicals from your water. We always recommend having your water tested if you are unsure of the quality.

Here are some categories to help you choose from all the options available.

Carbon activated filters

Chlorine, Heavy Metals & Sediment Reduction 

Chlorine, Chloramine, VOC's, Heavy Metals, Sediment & Scale Reduction

Pesticides, Chemical Reduction, and Sediment Reduction.

Fluoride & Arsenic Reduction


What pre filters do I need for a UV system?

When you have a UV system it is important to protect the UV from becoming discolored and dirty to allow for full UV effectiveness.

Pentair certified water filters for a twin filter system with a UV 




Pentair certified water filters for a triple filter system with a UV