How Does a Whole House Water Filter Work

How Does a Whole House Water Filter Work featured photo

Every household needs clean and safe water, whether it’s for drinking, cooking, or bathing. Unclean water is not only gross but is also a major health hazard. For your and your family’s sake, you should consider water filters like a whole-house water filter system.

A whole-house water filter works at the point-of-entry to your home and works by filtering all the water that comes into your home through faucets, toilets, showerheads, and all other water taps. Water goes through three main filtering stages: pre-filtration, main water treatment, and post-filtration.

How exactly a water filter works would vary and depend on the type of filter used in the system. Some water filter systems even combine at least two filters to provide the safest and cleanest water.

In this article, we’ll take a close look at exactly what a whole-house filter is, how it works, and the pros and cons you can expect from one.

What is a Whole House Water Filter?

For every household, clean and safe water is essential. Whether you’re using it for drinking, cooking, bathing, or cleaning, it’s important to avoid and prevent contact with harmful chemicals that can often be found in water.

If you notice sediments, particles, discoloration, or a rotten egg-like smell in the water from your faucet, it’s time to rethink your household’s water filtration system.

If you’re thinking of installing one or upgrading your current water filtration system, you might want to consider a whole-house water filter.

A whole-house water filter system is a water filter system that provides clean and filtered water to all water sources and faucets in your home.

Whole-house water filters are Point-of-Entry (POE) filters. This means they’re installed right where the main water line enters your home. Seeing as this is where the filter is installed, what it does is filter out all the water that enters your home.

Whole-house water filter systems filter and ensure only clean water comes out of all your faucets, showerheads, toilets, and all water taps. The filtering system also ensures your water-using appliances use only clean and safe water.

And because it’s placed before your water line splits into cold and hot water, you can also enjoy clean and filtered hot water for bathing.

Whether you’re using city-provided water or water from your private well, the water goes through the essential filtering systems before being split into different water taps for you and your family to use.

What does it remove?

Generally, a whole-house filter is able to remove the following:

  • Sediments
  • Contaminants
  • Harmful chemicals
  • Chlorine and chlorine smell
  • Water hardness
  • Foreign particles and impurities
  • Microorganisms
  • Iron
  • Sulfur
  • Arsenic
  • Pesticides

How Does a Whole House Water Filter Work?

How a whole-house water filter system works could vary greatly depending on the brand, construction, and type of filter used. But generally, a whole-house water filter system goes through three filtration stages:

Stage 1: Pre-Filtration

The pre-filtration stage is very important for any water filtration system. At this stage, the pre-filter works to block and remove large objects like sediments, sand, rust, and silt among others.

Not only does the pre-filtration stage remove any large unwanted matter from your water but it also works to protect the main filters in your system.

Large matters and waste will clog and quickly damage your filtering system. What the pre-filtration stage does is prevent this possible damage and instead prolong the filter’s life.

Usually, there’s only one pre-filter stage but some advanced filtration systems have more than one of these.

Stage 2: Main Water Treatment

The key to cleaner and filtered water lies in the main water treatment stage. This is where most water contaminants and pollutants are removed.

Depending on the type of filter media used, this stage can remove and block a variety of contaminants.

Common filter types include sediment filters, carbon-based filters, KDF filters, and UV light filters. We’ll discuss more on these later.

Water softeners are also quite common and popular, though they’re not technically considered water filters. What they do is soften hard water, which is also a common issue across the country.

Stage 3: Post-Filtration

Any water filtration system has a third and final step – the post-filtration stage.

This seems like a small and minute part of the process but it makes a whole lot of difference. This gives the water a final touch before sending it back to your plumbing system and into your home.

This stage further improves the water’s taste, color, and overall quality. And if there are any remaining particles or sediments in the water, this final stage filters them out as well.

Types of Whole House Water Filters

There are four common types of whole-house filters and they all differ in how they work and what they filter out from your water:

Sediment filters

Sediment filters remove mostly large particles in water that can likely clog your plumbing system. They come in different sizes, often from 0.5 microns to 50 microns. This size range reflects the pore size of the sediment filters.

These filters need changing about every six months.

Carbon-based filters

Carbon-based filters are an economical and popular choice for whole-house water filter systems. These filters can remove and filter out chlorine, chloramine, and other disinfection byproducts.

This type of filter has activated carbon, which is the only filter media recommended by the US Environmental Protection Agency (EPA) to remove organic contaminants, pesticides, and herbicides.

KDF filters

KDF, or Kinetic Degradation Fluxion, filters are capable of removing and filtering a variety of water contaminants including chlorine, lead, iron, nickel, hydrogen sulfide, and other heavy metals.

These are usually used as an additional layer to another type of filter.

UV light filters

What UV light filters do is kill living organisms that might be in your water. These organisms include viruses, bacteria, parasites, algae, and fungi.

They’re not much of a main filter as they don’t filter out and remove large particles and sediments. Instead, they kill harmful organisms that might be in your water. This makes them a great additional filter layer as well.

Whole House Water Filter Advantages

If you want to achieve any of the following, consider installing a whole-house wtaer filter system:

  • Provide your house with clean water on every tap and faucet
  • Drinking water smells and tastes cleaner and better
  • Remove foreign particles and contaminants from your home’s water
  • Prevent health risks due to dirty and contaminated water
  • Prevent damage to pipes and plumbing
  • Prolong the life of water-using appliances
  • Improve skin and hair health
  • Target specific water concerns and issues

Whole House Water Filter Drawbacks

  • High initial installation cost: Whole-house water filter installation can typically range from hundreds to thousands of dollars. It’s a pricey investment but many find it worthwhile in the long run.
  • Decreased water pressure: After installing the filter, you may find the water pressure to decrease due to the controlled speed of the water supply as it is being filtered.

Point-of-Entry Filters vs Point-of-Use Filters

Opposite of POE whole-house water filters are under-sink and countertop filters which what we call point-of-use (POU) filters.

These filters don’t treat and clean all water that comes into your home. Instead, they’re attached to a single or some specific fixtures. They can typically be found in kitchen faucets, where people need clean water the most for cooking and drinking.

POU filters are a great alternative to POE filters if you only need to clean the water that comes into your kitchen faucet and if you’re not dealing with water issues in the rest of the house.

If you are, however, dealing with issues with all other faucets in your home, a whole-house water filter might be your best bet. For a more in-depth comparison check out our guide to whole house water filters vs. under sink filters.


Clean and safe water is essential for every household. If there are contaminants, foreign particles, and an odd smell to your house’s water, you should start looking into water filter options.

A whole-house water filter is one of these options and what it does is clean and filter all the water that comes into your home. This means that all faucets, showerheads, toilets, and all other water taps have clean and now-filtered water. To ensure the safest water, this filter has three stages: (1) pre-filtration, (2) main water treatment, and (3) post-filtration.

And that has been our answer to the question, “how does a whole house water filter work?” and more. If you have more questions for us, please don’t hesitate to reach us below!

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