Whole House Water Filter Cartridge Types and Sizes – Overview

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Whole house water filters provide you with clean, fresh, and pure water. But what exactly do these filter systems remove? And how does your water filtration system differ from that of your neighbor’s?

Well, perhaps the water quality issues you’re facing differ from what your neighbor has to deal with, too. As such, the type of whole house water filter, or cartridges, you need also vary.

For instance, some water filters are designed to remove large floating particles like sand from water, while others remove chemicals.

For this reason, you need to determine the exact issue with your water before purchasing the right filter. Therefore, in this guide, we’ll discuss various whole house water filter cartridges types and sizes, and try to determine which might suit your needs.

Key Takeaways

  • Physical whole house water filter cartridge types:
    • Sediment filters (surface, depth, absorptive) – trap solid particles.
    • Ultrafiltration cartridges – remove proteins, colloids, parasites, and other contaminants larger than 0.01 microns.
    • Reverse osmosis membranes – Reject even the tiniest of particles as small as one-thousandth of a micron.
  • Common chemical whole house filter cartridge types:
    • Granular activated carbon – highly adsorbent, porous material ideal for removing chemicals and improving water taste and odor.
    • Carbon blocks – made of powdered activated carbon. Ideal for broad contaminant removal.
    • Catalytic carbon filter cartridges – even more effective than activated carbon. Also remove chloramines.
    • KDF filter cartridges – use redox reactions to eliminate water contamination.
    • Iron filters – remove iron, manganese, and sulfur.
    • Ion exchange filters – removes arsenic, sulfate, and more.
    • Activated alumina – used to adsorb arsenic, fluoride, uranium, and thallium.
    • UV purifiers – use ultraviolet light to kill microorganisms.
  • Water filter cartridge sizes:
    • 5×10 inches (point of use)
    • 5×20 inches (whole house)
    • 5×10 inches (whole house)
    • 5×20 inches (whole house)

Physical Whole House Water Filter Cartridge Types

Physical filters are used to remove solid particulates from your house water. For instance, if your water contains dirt like sand, silt, or sediments, physical filters are great to get rid of those.

Sediment Filters

The first whole house water filter cartridge type we’re going to discuss are sediment filters.

There are 3 subcategories here:

  • Surface filters
  • Depth filters
  • Absorptive filters

All trap solid particles inside one or more layers of filter media, allowing only clean water to flow out.

Note that most physical filters won’t remove chemicals, heavy metals, salts, and microscopic organisms from your water. Instead, they only target large bits and pieces usually over one micron in size.

Surface Filter Cartridges (Pleated)

Typically known as “pleated filters” (due to acorn-shaped structure), these whole house filter cartridges contain a thin sheet that traps all the dirt.

The pleated arrangement gives these filters more surface area. Hence, they have more capacity to hold particles, offering filtered water for longer.

What else is good? They are washable and reusable at least a few times, so you won’t be spending money frequently.

Depth Filter Cartridges (String Wound, Melt Blown, Spun)

A big swig of water, followed by dirt and rust in your mouth, is perhaps the most terrible experience!

Fortunately, depth filter cartridges save the day. These filters remove rust, sediment, and other dirt from water by forcing it to pass through a thick wall of filter material.

Depth filters come in various materials, including glass fiber, cellulose, ceramic, polyester, and polypropylene.

What makes some of them unique is their graded-density structure. That is, as the water passes, the filter gets tighter, so it catches the big particles first and holds the small ones alike in its core.

The structure of gradual density filter cartridges prolongs their service life significantly, as clogging is postponed.

Big Blue Whole House Water Filter

Absorptive Filters

Absorptive filters have recently gained more popularity, and for the right reasons. They are designed in both depth and pleated format.

Many of these filter cartridges use electrokinetic absorption attracting and holding negatively charged microorganisms. Further, they even trap super small particles that typically pass through conventional filters.

Generally, they are designed to capture particles as small as 2 microns in size, but they can also capture colloidal matter smaller than 2 microns.

Ultrafiltration Cartridges

Ultrafiltration (UF) cartridges remove proteins, colloids, viruses, bacteria, parasites, pyrogens, and other organic substances larger than 0.01 micron in size.

Plus, some UF in use today also eliminate herbicides and pesticides while equally reducing water hardness and salt.

Reverse Osmosis Membranes

Reverse osmosis membranes filter out even the tiniest of particles. For instance, they can reject viruses and other microorganisms as small as one-thousandth of a micron.

Simply put, these membranes can remove almost anything from your water, whether tannins, pesticides, nitrate, heavy metals – you name it!

Micron Ratings

The micron is a standard measuring size used by filter manufacturers. For example, a whole house sediment water filter cartridge might be rated at 5 or 10 microns.

Wondering how much that is? Well, your hair is around 70 microns, and some sediment filters can capture particles in the submicron range – so pretty small.

The filters are given micron ratings by their manufacturers. They describe the effectiveness of removing particles down to a specific size.

Nominal vs. Absolute

Typically, a nominal micron rating means a filter blocks 80% or more particles of its rated micron size.

Simply put, a filter rated 1-micron nominal can remove around 80% of particles that are 1 micron or larger from your water.

On the other hand, absolute ratings indicate that a filter cartridge effectively eliminates all the particles down to a specific size. These filters are used where efficiency matters a lot.

For example, a whole house sediment filter cartridge rated at 10-micron absolute catches all particles flowing through it sized 10 microns or larger.

What’s important to understand is that, if a filter claims to remove Salmonella from your water, you cannot depend on a filter that promises 80% efficiency (i.e. nominal). So, you’ll definitely need to go with absolute micron ratings (perhaps a 3-log or 4-log rating at a bare minimum).

Besides, the problem with both rating systems is that there is no universal standard that guarantees consistency. For instance, some manufacturers of nominal filters consider 75% rejection satisfactory; others want at least 80%. Hence, the definition differs from maker to maker, and consumers do not have a way to verify claims.

Common Chemical Whole House Filter Cartridge Types

From pesticides to trihalomethanes, a variety of chemicals can make their way into your water supply. Nevertheless, with a reliable chemical filter, you can eliminate most or possibly all of them. Below, we’ve discussed some standard chemical whole home filtration cartridges.

Granular Activated Carbon Filtration

Made from highly adsorbent, porous material, granular activated carbon filters contaminants from water through adsorption and chemical reactions.

It’s among the most popular whole house filter media because apart from removing chemicals like pesticides and disinfection byproducts, it also eliminates bad taste and odor.

Granular activated carbon filter cartridges are more commonly used in whole house applications than carbon filter blocks (see below) as they allow for higher flow rates.

Water Filter Cartridge

Carbon Blocks

Carbon filter blocks are made of activated carbon glued together using a binder. The mixture is then molded and compressed to a cartridge filter of the desired shape or size.

Carbon blocks have a filter capacity of 0.5 to 10 microns nominal. Hence, they can easily reduce lead and in some cases even cryptosporidium and giardia in addition to reducing chemical content.

Catalytic Carbon Filter Cartridges

While typical activated carbon filters effectively remove the majority of chemicals from water, they do not eliminate chloramine (a chemical used more and more these days for tap water disinfection).

Chloramines are somewhat problematic. They are more stable than chlorine, but also much harder to remove. And they form unwanted byproducts which have shown to have health effects.

Since GAC does not remove chloramine properly, you need a catalytic carbon filter cartridge to get rid of the chemical.

KDF Filter Cartridges

KDF filter cartridges make use of redox reactions to eliminate water contamination. The copper-zinc blend can remove chlorine, lead, hydrogen sulfide, chromium, mercury, and more. What’s more, it prevents bacteria and other microbes from accumulating in the filter system.

The two major types of KDF are:

  • KDF-55 filter media
  • KDF-85 filter media

KDF is often added to carbon-based filters to target a much wider range of contaminants.

Iron Filters

Iron filters remove, well, iron which is common in well water. First, they convert soluble ferrous iron into solid ferric (rust) through oxidation. The rust is then trapped in the filter media.

Ion Exchange

Ion exchange whole house water filter cartridges target specific groups of contaminants that other filter types don’t even touch.

They are great for removing/reducing inorganic substances like arsenic, sulfate, and other negatively charged pollutants.

Activated Alumina

These filters are embedded with activated alumina granules. AA is mostly used to adsorb arsenic and fluoride. Other contaminants that can be removed include uranium and thallium.


These are known as ultraviolet filter cartridges for a reason. They have a bulb installed inside the canister that emits UV light to kill microorganisms like bacteria.

The ultraviolet light destroys the DNA of said microbes, hence inactivating them in the water so they can’t reproduce.

This feature makes UV filter cartridges different from conventional water filtration systems, where water typically passes through a filter media.

So if your water has fungi, cysts, algae, dysentery, salmonella, or any sort of bacteria or viruses, ultraviolet filtration cartridges are the best to get rid of them!

Whole House Water Filter Cartridge Sizes

Generally, there are four main types of water filter cartridge sizes:

  1. 2.5 x 10 inches
  2. 2.5 x 20 inches
  3. 4.5 x 10 inches
  4. 4.5 x 20 inches

Different Water Filter Cartridges and Membranes

2.5” x 20”, 4.5” x 10”, and 4.5” x 20” filters are commonly used for whole house applications. Although some people prefer smaller sizes (to save money), they drop the pressure flow, making it an unsuitable choice in most cases.

Moreover, you can also choose from proprietary sizes, but again, it’s not recommended because of two reasons:

  1. First, they are more costly.
  2. Second, it would be difficult for you to get suitable replacements in case of company closure or product discontinuation.

So, opting for a general filter size is always the right choice.

Flow Rates

Flow rates vary depending on the type of filter media and cartridge sizes.

For instance, a larger cartridge will always provide a higher flow rate as compared to a smaller one. Also, sediment filters with large micron ratings have higher flow rates than carbon block filters of equal size.

So in general, the tighter and the smaller a filter cartridge, the slower the maximum flow rate.

Let’s look at a few examples:

A manufacturer might have rated his 4.5 x 10 inches filter cartridge as:

  • 10 gpm (50-micron absolute pleated sediment filter)
  • 8 gpm (25-micron absolute poplypropylene spun sediment filter)
  • 3 gpm (25-micron nominal granular activated carbon filter)
  • 4 gpm (5-micron nominal activated carbon block filter)

Which Type of Filter Cartridge For Your Water Problem?

The type of water filter cartridge you need depends on the water issues you are experiencing.

Also, whole house filters provide the convenience of experimenting with different filter cartridges to find the one that works best for you.

Generally, we recommend one or more sediment pre-filters as your first defense line. They serve the purpose of holding dirt and debris to protect subsequent filter stages.

Next you can install carbon filtration followed by more specialized filter cartridges to target your specific water contamination.

If you have any questions about whole house water filter cartridge types or whole house water filter sizes, please don’t hesitate to leave a comment below!

About the Author Gene Fitzgerald

Gene Fitzgerald is one of the founders of BOS and currently head of content creation. She has 8+ years of experience as a water treatment specialist under her belt making her our senior scientist. Outside of BOS, Gene loves reading books on philosophy & social issues, making music, and hiking.
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