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What Are Whole House Water Filters and How Do They Work?


Whole-house water filters provide cleaner, safer water to every tap in your home. Most commonly needed with well water, each whole-house water filter is typically designed to address a specific problem that impacts not just drinking water but also the water you cook, bathe, and clean with. 

Some whole-house filtration systems tackle unpleasant tastes and odors that stem from excess chlorine (a common problem with municipal/city water), while others work to reduce typical well-water problems like too much sediment, iron, sulfur or arsenic. Regardless, they are installed where your main water line enters your home 

Choosing the best whole-house water filter for your home will depend on your water source – municipal or a private well – as well as what’s in your water. Don’t know which option is right for you? The first step is getting your water quality tested, but you may already see some clues around your home.

How Do I Know If I Need a Whole House Water Filter?

While some contaminants can go unnoticed, others are readily apparent to members of a household (and guests).* Problem water can leave stains, have a foul odor, be discolored or taste bad. 

For private well owners, signs that you may need a whole-home water filter system include:

For municipal water users, signs include:

  • Chlorine or bleach-like taste or odor
  • Sediment or discolored water

However, it’s not always easy to tell what’s in your water just by looking at it or smelling it. Your senses won’t detect some contaminants, such as arsenic. Invisible, odorless and tasteless, arsenic in water comes from a chemical element naturally found in the environment. Exposure to this contaminant can become toxic over time. Furthermore, prolonged exposure to arsenic has been linked to  skin and health conditions.

So how do you know if you need a whole-home water filter if you can’t tell exactly what’s in your water? Testing your water is the only way to know for sure if there is a problem – and how best to fix it.

How Does a Whole House Water Filter Work?

All water goes through an extensive journey before it reached your faucet. It begins as rainwater from a natural source such as a river, lake or stream. Municipal supplies use these surface waters as a source and private wells are supplied by water that has moved to underground aquifers. Along the way water can pick up naturally occurring and man-made contaminants.

Municipal water goes through a journey before it reaches your faucet. It begins from a natural source, such as a lake, river or the ground, and flows through the earth into a treatment center. Along the way, water can pick up dirt, particulates and other contaminants that can increase water hardness levels and cause other problems. 

Although the treatment center processes and treats the water before distributing it to your home (if you have municipal water), not everything that could have a negative impact is addressed — especially with new and emerging contaminants such as pesticide, PFOA/PFOS, and pharmaceutical runoff affecting water sources. Many treatment centers aren’t set up to treat water for contaminants not yet regulated by organizations that oversee municipal water safety, like the U.S. Environmental Protection Agency. Further, water can pick up more contaminants as it travels from treatment centers to your home from aging infrastructure and old lead piping. For some of these water concerns, the best solution is a drinking water filtration solution, like a reverse osmosis system. For others, a whole-house filter can help.

If you use well water, your water comes directly from an underground source called an aquifer, and it is pumped from your well into your home to flow through your pipes. Well water can contain contaminants such as iron, hydrogen sulfide, sediment, silt, arsenic as well as have a low pH level (acidic water). That’s why it’s important to look for a well water filtration system that’s specifically designed to treat your individual water issues.

Whole-House Water Filters: FAQs

There’s a lot to know about whole-house water filtration. Here are a few frequently asked questions to help guide your research and your choice of whole-house water filter systems.

What Are the Types of Whole-Home Filters?

There are many types of whole-home filters; each works in different ways to address different water-quality issues. For example:

  • Sediment filters “trap” particles within the filter media to reduce the presence of sediment, clay and silt.
  • Iron filters can convert iron to filterable particles and retain it within the filter media so it doesn’t get into your home’s water.
  • Sulfur filters remove the rotten-egg odor from your water by way of special media.
  • Low pH or acidic water can be neutralized, and the pH level increased, through the use of limestone media.
  • Arsenic can be removed by specialty filter media designed specifically for arsenic reduction.
  • Activated carbon filters can reduce chlorine taste and odor.

A water test can help you decide which type of whole home water filter is best for your needs. 

Do Whole-House Water Filters Work?

Yes, but not all whole house water filter systems are created equal. To find one that will reliably and effectively reduce the presence of contaminants in your water, look for products that have been certified by a third-party organization like the Water Quality Association (WQA), National Sanitation Foundation (NSF) or International Association of Plumbing & Mechanical Officials (IAPMO). That means the equipment has been independently tested and data has verified its safety and performance. 

For example, Culligan’s Aquasential® Smart High Efficiency Cullar Water Filters have been tested and certified for the effective reduction of aesthetic chlorine taste and odor. Similarly, the Culligan Aquasential® Smart High Efficiency Iron-Cleer® Filters have been certified for the effective reduction of iron.

How Long Do Whole House Water Filters Last?

The lifespan of a whole-house water filter will depend  on the quality of the equipment, the amount of contaminants in your water, the regularity of system maintenance by a filtration professional and the amount of water your home uses. It’s also important to note that individual components of a system have differing lifespans. To extend the lifespan of your equipment, look for a water-filtration company that offers high-quality products with robust warranties, filters made to last several years and complete service packages from reputable, trained technicians who know the system well. 

In general, you can count on a whole house water filter to last longer than other solutions like faucet or fridge filters.

Where Should a Whole House Water Filter Be Installed? 

Whole-house water filters are installed near your main water shutoff valve. This is generally located somewhere on the perimeter of your home, often in the basement or a utility closet. If you’re using municipal water, the valve usually faces the street, but well-water valves can be on any side of your house.

It is best to install a whole house filter system indoors to protect the system from the elements. If a system must be installed outdoors it is important to select a filter system that has been designed and rated for outdoor use. Culligan offers many options for these types of systems.

How Much Does a Whole-House Water Filtration System Cost? 

The cost of a whole house water filtration system depends on the type and size of the filter and how much water you use. 

However, a good system doesn’t act as a drain on your bank account. Instead, it uses smart features to help you track and reduce water use, quickly identify emerging maintenance needs, automatically notify your local water-treatment expert of any issues that arise and more. They also don’t have to be replaced as often as simpler systems such as faucet filters.

Is a Whole House Filter Worth It? 

Yes. Unlike point solutions, the benefit of a whole-house water filter system is that it provides filtered water to your entire home. It treats a large volume of water while protecting your investment in plumbing fixtures and water-using appliances, and it improves water quality at all your faucets.  

How Do I Choose the Best Whole-House Water Filter for My Home?

Culligan Water has several types of filters designed to reduce different types of contaminants. However, your water quality will depend on where you live and the source of your water supply. A water test is the best way to find out what’s in your water. Based on your test results, your local Culligan Water expert can help you choose the right whole-house water filter for your home to address your individual water-quality issues.

Culligan whole-home water filtration systems have helped improve the water in thousands of homes throughout North America. Our top whole-house water filters include:

Aquasential® Smart High-Efficiency Water Filter: Ideal for homes that use well water, this complete water-softening and filtration system helps reduce sediment and contaminants found in well water to deliver cleaner, safer, better-tasting water.

Aquasential® Smart High Efficiency Iron-Cleer® Iron Water Filter: Designed to improve your water quality without chemicals, this system can help eliminate staining, odors and tastes by reducing the presence of iron.

Aquasential® Smart High Efficiency Sulfur-Cleer® Sulfur Water Filter: To eliminate the rotten egg smell in your water, this water filtration system helps reduce the presence of contaminants like hydrogen sulfide, leaving you with fresher-smelling water.

Aquasential® Smart Arsenic Reduction Water Filter: This filtration system uses advanced technology to provide maximum arsenic absorption. With high-visibility meter readings and a hardy design, this system is as reliable as it is high-quality.


If you’re ready to find the water filtration solution that meets your home’s needs, start by getting the right information. Schedule your free, in-home water test and consultation today.


*Contaminants may not be present in your water.

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