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What is a Whole House Water Filter and How Does It Work?

Posted by John Woodard on November 30, 2023

 A whole house water filter is a filtration system that treats water where the main water line enters your home, ensuring the water that flows from every faucet, every showerhead, and even in your washing machine, is clean and filtered. Whole house water filters are point of entry (POE) filters. They are gateways for your tap water, and allow only fresh, filtered water to flow to your faucets and appliances.

What does a whole house water filtration system do?

A whole house water filtration system can do exactly what you need it to do, meaning it can remove whichever contaminants you do not want in your home’s water supply. Depending on your home’s water source, you may want to reduce water hardness, to remove sediment, or to eliminate the smell of chlorine. Whole house water filters vary in complexity, but for whichever water quality problem you experience, there is a whole house filter that can provide the solution.


child at kitchen sink

What are the different types of whole house water filters?

There are five main types of whole house water filters: water softeners, ultraviolet purification systems, sediment filters, carbon filters, and acid neutralizers. Each filter addresses a different contaminant or water quality issue, so the right filter for you will depend on a thorough understanding of the composition of your water. Below you will learn about the five types of whole house filters, the contaminants they remove, and how you can improve your home’s water quality. Also, a home water testing kit or a lab water analysis are useful tools to determine what exactly is in your water and to help you choose the best whole house filter for your home.                                                                                                             

1.    Water softeners

A water softener is the solution if you have hard water, the most common water issue we face. Hard water is caused by a high concentration of dissolved minerals, specifically calcium and magnesium, and can wreak havoc in your home. If you have stiff, faded laundry, soap scum in your shower, or chalky dishes, you most likely have hard water. Hard water also causes scale that clogs your pipes, decreases water pressure, and shortens the lifespan of your appliances. Hard water can even affect your body, rendering your skin dry and itchy and your hair dull and frizzy. If your home is plagued by hard water, a whole house water softener is an investment that will ultimately save you a lot of money, as you will not have to pay for expensive repairs or replacements, such as your water heater due to scale build up.

How do water softeners work?

Water softeners remove hardness-causing minerals through a process called ion exchange. Calcium and magnesium have positively charged ions, while the porous resin beads inside a water softener have negatively charged ions. Since opposites attract, when calcium and magnesium encounter the resin, they become trapped, allowing softened water to flow through. With proper maintenance, the average lifespan of a water softener is 15 years, so you and your home could reap the benefits of softened water for years to come.

Learn More: What is Hard Water?

2.    Ultraviolet purification systems

Ultraviolet purification is the solution if you are concerned about the presence of living organisms, such as bacteria, viruses, parasites, and fungi, in your water. If using well water, in the event of a natural disaster, or if you are put on a boil water advisory, an ultraviolet purification system can ensure your access to safe, filtered water. Plus, ultraviolet purification systems do not use chemicals and do not waste water.

How do ultraviolet purification systems work?

Ultraviolet purification systems utilize UV light to damage the DNA of living organisms, rendering them unable to reproduce and unable to spread disease in the water supply. However, ultraviolet purification systems are most effective when water is first treated by a different filter, such as a sediment filter, because dirt and debris shield microscopic bacteria, viruses, etc. from UV light. Yet, when water is pre-filtered, ultraviolet purification systems can neutralize 99.9% of living organisms, making them a great addition to whole house filtration systems that give you peace of mind and safeguard your home water supply.

Learn more: What is a UV Water Purifier and How Does It Work?

3.    Sediment filters

A sediment filter is an effective solution to maintain a clean, refreshing water supply and to prevent damage to your home. Sediment filters trap and remove a myriad of contaminants from water, such as dirt, sand, clay, and rust flecks from aging pipes. If not addressed, sediment can clog your pipes, decrease water pressure, and damage your appliances, forcing you to pay for expensive repairs. Sediment can even make your water unsightly and cloudy: a condition called turbidity.

How do sediment filters work?

Sediment filters work through mechanical filtration, meaning they physically block sediment from entering your water supply. They have pores that are too small for particulate matter to pass through, but that allow water to flow through unhindered. A simple yet powerful concept, sediment filters are often the first line of defense for a whole house filtration system, as they improve the effectiveness of other water filters, by prolonging the life of carbon filters and water softeners, or ensuring UV systems operate at peak performance.

Learn More: What is a Sediment Filter and How Does It Work?

4.    Carbon filters

The primary function of carbon filters is to remove chlorine from water, as well as its chemical taste and smell. Chlorine is used by municipal water supplies to kill bacteria in water and in water pipes. While still safe to consume, water that smells and tastes like chlorine is unsettling. Carbon filters not only improve the taste and smell of your water supply, but also the safety. With a carbon filter, you can be confident that you are not consuming harmful substances from your tap water, as chemicals like pesticides and herbicides are also significantly reduced.

How do carbon filters work?

Carbon water filters contain activated carbon that has an abundance of pores along its surface and infrastructure. When water runs through the activated carbon, organics and chemicals are captured or altered by a process called adsorption, and clean water emerges on the other side. Activated catalytic carbon also facilitates the reduction of chloramines from your water. Chloramines, a disinfectant alternative to chlorine, are used by many municipalities to treat city water supplies. Chloramines are notoriously difficult to remove from water, but catalytic carbon can break apart the chloramine molecule with greater efficacy than standard activated carbon. 

Learn More: Activated Carbon Filters 101 

5.    Acid neutralizers

An acid neutralizer is the solution if you have acidic water. Acidic water has a pH of less than 7 and can cause serious damage to your pipes and appliances, including corrosion, leaks, and green-blue stains. Pure, neutral water has a pH of 7, but becomes acidic as it absorbs carbon dioxide during the process of precipitation. Therefore, many wells have acidic water since their supply is often from shallow groundwater. Chemical runoff can also cause acidic water, so it is important to protect your home and your health with an acid neutralizer.

How do acid neutralizers work?

Acid neutralizers use calcite to decrease the acidity of water. Calcite is a mineral that is rich in calcium and is very high in alkalinity: the opposite of acidity. An acid neutralizer tank is full of calcite. When acidic water enters the tank, the calcite dissolves, neutralizing the water and raising its pH. A properly sized whole house acid neutralizer will raise the pH to neutral or higher and will prevent damages caused by acidic water.

Learn More: What is Acidic Water and How Do You Treat It?


What do whole house filtration systems remove from water?

Whole house filtration systems remove a variety of contaminants from water and treat different water quality issues. Your home’s water quality will determine which contaminants need to be removed, and in turn, which filter is the best choice for your home.

Water softeners remove:

  • Dissolved minerals that cause hard water – calcium and magnesium
  • Dissolved iron and manganese
  • Scale

Ultraviolet purification disinfects:

  • Bacteria
  • Viruses
  • Parasites
  • Fungi
  • Algae

Sediment filters remove:

  • Dirt, sand, and clay
  • Rust flecks from aging pipes
  • Turbidity

Carbon filters remove:

  • Chlorine
  • Chloramines* (If using catalytic carbon)
  • Pesticides and herbicides
  • Trihalomethanes
  • Bad tastes and odors

Acid neutralizers reduce:

  • Acidity imbalance (low pH)
  • Acidic corrosion


Whole house filters vs. under sink and countertop filters

Whole house water filters are point of entry (POE) filters, which means they are installed where the main water line enters your home and filter all the water that is distributed throughout your home. In contrast, countertop and under sink water filters are point of use (POU) filters. They attach to a single fixture, such as the kitchen sink, or are simply placed on the countertop, and only filter the water that you use in that specific place.

Whole house water filters treat every drop of water in your home. The water you use to drink, cook, shower, brush your teeth, do laundry, and clean is all filtered. Your plumbing and appliances are also protected. Under sink and countertop filters are mainly used to filter the water that you drink, cook with, and maybe run to an ice maker in the refrigerator. Under sink and countertop filters are less expensive than whole house filtration systems, but they do not protect your pipes and appliances, and only provide one source of filtered water in your home.

How much do whole house water filters cost?

The short answer is it depends. It depends on the complexity of the filtration system that you need to treat your particular water quality issue. The long answer is the cost of a whole house water filter is between a few hundred dollars and few thousand dollars. However, keep in mind that whole house systems protect your pipes and appliances, so you will not have to pay for expensive repairs or replace your appliances as often. Also, most people spend between $400 and $1,000 on bottled water per year. A whole house filter eliminates the need to buy bottled water, so the benefits far outweigh the costs. If a whole house water filter solves your water quality issue and brings you peace of mind, it is worth every penny.


What are the advantages and disadvantages of whole house water filtration systems?

Advantages of whole house water filtration systems:

  • Remove a multitude of contaminants from water, customized to your specific water issues
  • Improve the smell and taste of water
  • Extend the lives of appliances
  • Prevent damage to pipes
  • Give you a higher level of peace of mind: Every drop of water that flows through your home is filtered. You can drink, cook, clean, and bathe with filtered water. Also, the water entering your home is disinfected from living organisms. If you have well water, this is a must. If you have city water, this is an insurance policy to protect your family if the city is unable to.
  • Eliminate the need for plastic water bottles: Less waste is created and avoiding single-use plastic is good for the environment.

Disadvantages of whole house water filtration systems:

  • Initial cost: Whole house water filters cost between a few hundred and a few thousand dollars.
  • Professional installation: Whole house water filters usually need to be installed by a licensed plumber, which adds additional cost.
  • May decrease water pressure: The water supply runs through the filter at a certain speed. If you are taking a shower, doing laundry, and running your dishwasher at the same time, you may notice a decrease in water pressure. However, if you already struggle with reduced water pressure, consider supplementing the filtration system with a water booster pump.


water flowing from shower head

Do I need a whole house water filter?

You may need a whole house water filter for a variety of reasons. If your home’s water supply contains a troublesome contaminant or generally poor quality, there is a whole house filtration system that can be the solution.  If you are on well water, you may need to remove sediment and to disinfect your water. If you are on city water, you may want to rid your water of the smell and taste of chlorine. If you have hard water, you will reap countless benefits by installing a water softener. A whole house filtration system can be designed to remove anything that is troublesome from your water.

If you are only concerned about filtering the water that you drink and cook with, a whole house filtration system may not be the best choice for you. An under sink or countertop filter would make more sense and be more economical. However, if you want the peace of mind that the water flowing from all your faucets and through your appliances is safe and filtered, then yes, you need a whole house water filter.


Our goal is for you to have a clean, trustworthy water supply that is kind to you, to your appliances, and to your home. If you have any further questions regarding whole house water filtration or how to choose the best filter for your home, please don’t hesitate to contact us. 

Comments 1-10 of 11

I found it helpful when you said that a whole house water filtration system could remove a multitude of contaminants from water and improve the smell and taste of water. With this in mind, I will convince my husband to hire a professional that could install a reliable water filtration system for us within the week. We want to ensure that our children will only consume clean and safe water that is free from any type of contaminants that could o-put their health at risk.

kia N on December 20, 2021

I recently got whole house filtration system. However, the seller promptly went out of business. I have no technical or service support. I have no instructions or warranty. What do you recommend I do?

Rocket C on September 01, 2021

We have a well – it’s about 30 years old. We do not have a softener as we don’t like how the water feels or tastes when it’s softened. Over the past couple of years, the water taste has changed. When we fill up the little sitting pool in the summer – the water will turn brown after it goes thru the filter, so we know we have iron. Before getting any kind of whole-house filtration system, I assume we need to have the water tested? What do you recommend for that. Thank you.

D.J. on April 06, 2021

Interested in a whole house water system and installation.

Thank you


Yvonne on March 19, 2021
Great articles/letters. Good info on what I should do to find out what I need to do. I am in a new home to me and see this equipment but the co. on the label is reluctant to service it. I just needed to know what to do. The water here smells a faintly “rotten eggy”.

And the filter I see is quite dark gray.
Thanks for the explanation.

Deb on September 21, 2020
I’m really sorry you are going through the cancer treatment. If the system is still in good condition I would definitely have someone come and clean it out and disinfect with something like Lysol. Then rinse well and refill the large tank with the recommended level of pellets. Place new filters in all the filter holders. Run it according to directions. Actually once it’s up and running there’s not much to do except checking the pellet level. I would also have a new reverse osmosis system placed under your kitchen sink. It removes EVERYTHING including fluoride which definitely causes cancer. The big softening tank will remove minerals, iron lead etc. The RO system takes pretty much everything else out. The filters must be changed on a strict schedule according to the manufacturer. If your not able to change filters yourself then a plumber can do it. Or— you could have a professional company put in a system and maintain it for you. Good luck with your treatment!!
Katie on March 05, 2020
Our city gives us bottle water. Worden Montana. We have water problems. Would a whole house filter help? It’s going to take up to two years to fix the water. They need to build a plant
Heather CAll on July 31, 2020

Hello Allison,

There are whole house filtration systems that are rated for lead reduction. You can check the manufacturer’s spec sheets to see what contaminants individual whole house filters have been tested to remove.

However, if there is lead in your water, you might also consider installing an under-sink system like reverse osmosis or the Neo-Pure TL3. Lead is a very nasty contaminant with serious health implications, so remain vigilant about testing your water to make sure the lead content is being removed. An under-sink system will further ensure that no traces of the metal are making its way into your drinking water.

John Woodard, Master Water Specialist on December 17, 2019
Hello – can these systems remove lead? There is an old service line to my house but the cost to change that versus the cost of a whole house filter is quite different.
ALlison on December 17, 2019
Hi Elizabeth,

Without a water analysis of the well, it is difficult to provide any recommendations for best ways to improve the water’s quality. I am thinking what you describe is a water softener, a tall tank (should have a smaller tank close by that holds the large white pellets) Inside the tall tank is softening resin. Depending on how long it has been unused, it is possible that the resin is shot and will no longer function properly to remove hardness causing minerals. A local water treatment professional should be able to come check it out for you. Just flushing water through it may not help. A water softener when functioning properly, will only remove the hardness minerals. Things causing odor and stains might be something a softener cannot address and will need additional steps to obtain the quality of water you desire.

I would recommend you have a water analysis done to understand the composition of the well water. It is possible that your landlord may have to have it analyzed periodically and can share the results with you. If not, here is a test kit that is a box of empty bottles that you fill up with the water you want to test and send it to the lab: In about two weeks you will get the results on 75 parameters which typically gives us all we need to know to make your water better. We would be happy to look over the report with you and provide our recommendations.

I wish you well on your cancer fight and so glad to hear you are doing well. Let us know how we can help.

John Woodard, Master Water Specialist on November 20, 2019
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