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All whole house water filters provide your household with the same benefit – clean and filtered water. However, the filtration methods used by the many different types of whole house water filter cartridges are completely distinctive.
This is because the quality of water varies considerably between towns, cities, rural and urban areas. Thankfully, many filter systems are not run-of-the-mill units. Instead, they are almost entirely customizable to deal with your unique water problem.
Whether you are dealing with visibly large particulate matter, invisible waterborne bacteria or heavy metals, there is a filter cartridge out there for you.
However, with so many options it’s challenging to decide for the best one. This guide is all you need to figure out what to buy – in terms of both cartridge type and size – in order to get the cleanest filtered water.
So, here is our guide on whole house water filter cartridge types and sizes!
- 1 1. Physical Whole House Water Filter Cartridge Types
- 2 2. Chemical Whole House Filter Cartridge Types
- 3 Whole House Water Filter Cartridge Sizes
- 4 Your Ideal Type of Whole House Water Filter Cartridge
- 5 Conclusion
1. Physical Whole House Water Filter Cartridge Types
Does your water appear turbid and have traces of dust particles swishing around when you fill up a glass? Lucky for you, a physical whole house water filter cartridge will take care of it.
Physical filters, also known as mechanical filters, remove visible particulate matter like sand, dust, rust, silt, and clay from your water.
Whole House Sediment Filters
Let’s begin by discussing whole house sediment filter cartridges that utilize physical filtration to treat contaminated water.
Here are the three most well-known types of sediment filters.
- Surface filters
- Depth filters
- Absorptive filters
Sediment filters target floating contaminants over one micron in size.
They do not remove dissolved organic matter, heavy metals, salts, chlorine and chemicals. That’s why sediment filter cartridges are an excellent choice to pre-filter water before it enters other stages of treatment.
Surface Filters (Pleated)
Surface filter cartridges, also known as pleated filters, do not let sediment/solids enter the medium. Instead, they restrict them outside the filter media using their wide surface area.
Typically, pleated whole house filter cartridges work as long as their external surface area is fully covered with particles and then disposed of.
But some high-quality surface filters are relatively eco-friendly; they can be washed and reused multiple times. Thereby reducing maintenance costs considerably.
Pleated filters are best suited to treat uniform size contaminants. If there is a high degree of size variance, they may not be the best fit.
Depth Filters (String Wound, Melt Down)
Depth filters are used to remove a wide range of particles, including dirt, grit, sand, bits of rust and organic solids.
Made from carefully selected materials such as ceramic, polypropylene, cotton and glass fiber, cellulose and polyester, the cartridges trap particles as they flow through, preventing them from moving forward.
These filter cartridges often have superior dirt holding capacity due to a gradient-density structure: The first filter layer traps bigger particles. Moving on, the second layer is designed to restrict finer particles. And so on.
The unique structure of the filter cartridge makes it a perfect fit to deal with particles of varying sizes without clogging too soon.
Absorptive Filter Cartridges
Absorptive filters can either use pleated or depth formation for their cartridges. Most absorptive filters use electrokinetic absorption that pulls and holds negatively charged microorganisms.
Due to their unique design, these filters are more efficient at removing smaller particles (less than 2 microns) than the other two physical filter types.
Reverse osmosis is, perhaps, the only filtration technology that can remove contaminants down to 0.0001-micron size.
As water passes through the semipermeable RO membrane, it removes up to 99.9% of contaminants, including chemicals, heavy metals, bacteria, viruses, volatile organic compounds, pesticides and herbicides. It doesn’t get better than this!
Ultrafiltration is a physical water treatment process that features a hollow membrane to mechanically filter our tiny particles (as tiny as 0.01-micron size).
As water passes through a UF whole house water filtration cartridge, it is freed from most organic molecules and viruses, as well as a wide range of salts.
Some are even designed to remove pesticides and herbicides from your water, making it an ideal choice for all types of feed water.
On Micron Ratings
Physical water filter cartridges vary in their capacity to remove contaminants. Therefore, micron ratings are essential to determine the efficiency of the specific treatment method.
For instance, a 5-micron sediment filter will remove anything equal to or above the size of 5 microns.
The smaller the micron rating, the more precise filtration the filter will offer. For reference, human hair is rated at 70 microns. So, if a whole house water filter cartridge features a sub-micron rating, you can expect it to do a neat job.
Nominal vs Absolute Microns
The two used micron ratings for water filter cartridges are nominal and absolute.
If two filters sport the same micron rating, but one has an absolute rating while the other has a nominal rating, which is the better option? We’d say, absolute. Allow us to explain.
A filter with a nominal rating of 1 micron will trap 80% of contaminants equal to or bigger than 1 micron. On the other hand, an absolute rating of 1 micron suggests the filter will remove 99.9% contaminants rated at 1 micron.
Filters with absolute ratings are essential if you can’t risk the efficiency of water treatment. With a nominal micron-rated filter, you never know what will swim in your water even after being treated.
For example, if your feed water is at high risk from Salmonella, it’s unwise to invest in a filter that only promises to remove 80% of it. However, if you are only concerned with sediment, nominal-rated cartridges are still a good pick.
Unfortunately, there is no fixed industry standard for nominally rated filters. Some manufacturers claim that nominal filters offer 75% accuracy, while others accept 80% precision. It’s a blind spot that better be avoided.
2. Chemical Whole House Filter Cartridge Types
Chemical whole house water filter cartridges are designed to remove a wide range of contaminants from your water utilizing chemical processes. They can eliminate chlorine, herbicides, fluoride, nitrates, pharmaceuticals and many other harmful contaminants, ensuring better health and wellness.
Here, we will go through the most commonly used chemical whole house filter cartridges.
Granular Activated Carbon-Based Whole House Filter Cartridges
The most popular and commonly used water filter, granular activated carbon, treats your water through adsorption. Activated carbon is a porous media with an extremely high surface area.
Besides removing chlorine, herbicides and other organic chemicals, GAC filters can also be used to adsorb odor-causing impurities.
A GAC filter is made using tiny loose granules of carbon held together inside a cartridge. Compared to carbon block filters, GAC filters allow for faster flow rates and last much longer.
However, this means that water spends less time in contact with the filter media, reducing purification rates.
Carbon Block Filters
Carbon block filters are much more tightly packed than GAC filters. The compact nature of a block filter allows for more thorough filtration as even the smallest particles or contaminants cannot pass through the medium.
Most carbon block filters can easily remove a wide range of contaminants, including lead, cryptosporidium and giardia. They also improve the taste and smell of your water.
Catalytic Carbon Filter Cartridges
Many water utilities in the US now add chloramine instead of chlorine to disinfect water. The problem with chloramines disinfection is that they are much more difficult to remove. Plus, they react with organic substances in your water and produce unwanted byproducts.
Unfortunately, a standard activated carbon filter can’t effectively remove chloramines.
This is where catalytic carbon comes into the picture. Catalytic carbon whole house filters are a classification of activated carbon designed to remove chloramines and hydrogen sulfide from drinking water.
Ion Exchange Filter Cartridges
Ion exchange refers to the process of exchanging electrons with contaminants. These filter cartridges are helpful to target those contaminants that other technologies fail to eliminate.
Ion exchange whole house water filters can remove inorganic substances like arsenic, sulfate and various other negatively charged pollutants.
KDF is a unique blend of high-quality zinc-copper alloy. As water passes through the media, an oxidation/reduction process removes chlorine, lead, mercury and more.
KDF also prevents the growth of algae, fungi and bacteria in a filter system. KDF filter cartridges are typically used along with carbon filters to eliminate a wide range of contaminants.
Iron filters are specialized cartridges that remove iron and manganese from your water. Most iron filters remove both dissolved (ferrous) and undissolved (ferric) iron.
While tank-based iron filters backwash the filter media periodically to clean their filter bed, cartridge-type iron filters don’t. Therefore, they tend to clog faster.
Activated alumina whole home filter cartridges can be an effective treatment for water with high total dissolved solids (TDS) levels, arsenic and fluoride.
UV (ultraviolet) filters treat water quickly and effectively. They are primarily used as the last stage in a whole house water filter system.
A germicidal UV light bulb inside the cartridge attacks tiny microorganisms swimming in your water.
Nevertheless, the UV light doesn’t filter anything out. It only alters the DNA of living organisms like bacteria and viruses, including e coli, rendering them harmless.
Once the pathogens are deactivated, they can’t reproduce.
Whole House Water Filter Cartridge Sizes
Water filter cartridges come in four standard sizes.
- 4.5 x 10 inches
- 4.5 x 20 inches
- 2.5 x 10 inches
- 2.5 x 20 inches
For whole house filtration systems, it is advisable to use 4.5 x10 inches or 4.5 x 20 inches size. The larger the cartridge size, the better the flow rate it has to offer, and thereby does not reduce water pressure.
Some people also prefer using exclusive sizes for their whole house water filtration systems. Nevertheless, we only advise using generic sizes because:
- Standard-sized filter cartridges are inexpensive and readily available.
- Secondly, even if the company stops producing a particular cartridge, you can easily get replacements from another brand on the market.
Water Flow Rates
Water filter cartridges are generally sized using flow rate. Flow rate is typically expressed in gallons per minute (gpm).
Unsurprisingly, flow rates for filter cartridges differ considerably depending on the type of filter media and their size.
Of course, the larger the cartridge, the better the flow rate it will offer. Moreover, there will be a big difference in the flow rate between let’s say a sediment filter and a carbon filter of the same size. Here are some examples:
- 9 gallons per minute (25-micron PP sediment filter)
- 10 gallons per minute (50-micron pleated sediment filter)
- 4 gallons per minute (25-micron nominal GAC filter)
- 5 gallons per minute (5-micron nominal activated carbon block filter)
Your Ideal Type of Whole House Water Filter Cartridge
Finally, the burning question: Which whole house water filter cartridge should you go for? Since most POE systems feature multi-stage filtration, you can experiment with a few options.
We advise having at least one or two sediment pre-filters to treat the water before entering subsequent cartridges. Since carbon filters and KDF media target the most common impurities, they are a perfect choice as the second filter.
Finally, a UV cartridge at the end can reduce tiny microorganisms.
Nevertheless, you can customize a system to target your specific water quality. It is crucial to make the right decision and select the water filter cartridge that will tackle the unique problem with your water.
In conclusion, there are several different types of whole house water filter cartridges.
Sediment filters are the most popular physical whole house cartridges. They are rated in microns which describes how small of a particle they can catch.
Iron, KDF, carbon and ion exchange filters belong to the group of chemical whole house water filtration cartridges – and there are many more.
However, there are no more than 2 sizes for what we’d consider genuine whole house water filter cartridges: 4.5 x 10 inches and 4.5 x 20 inches.
The larger the size of a filter cartridge, the higher its maximum flow rate.
And lastly, your ideal whole house filter cartridge depends on your water quality and needs.
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Jason is the founder of Water Masterz and head of content creation. After six years in the industry, he has tremendous knowledge and first-hand experience on all things related to water treatment.
His credo: Not a single American should have to drink unhealthy water at home.