How Do Well Water Filter Systems Work?

Author: Jason Hollow - Published: 2022/09/28 - Updated: 2022/12/22

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Having a private well can be convenient, but it’s not without issues. For instance, you’ll probably need to filter your well water as it won’t receive any other treatment – unlike municipal water.

That’s where well water filtration systems come in, and that is why you need to understand how they work to choose the right system for you.

This guide will teach you how well water filters work, the different filtering systems available, and how to choose the right one for you.

So, here is our guide answering the question, how do well water filtration systems work?


  • Pre-filtration – This part of a well water filter system uses sediment filters to separate larger particles from the water, such as rust, silt, and sand.
  • Main treatment – A well water filtration system may use a combination of filters such as carbon, iron and KDF to eliminate traces of heavy metals, chemicals, and the like.
  • Post-filtration – This part often uses a UV filter to kill harmful microorganisms.

How Does a Well Water Filter System Work?

how do well water filters work thumbnail

A whole house water filter is installed on your main water line to filter any water as it enters your home.

Depending on its type, the filter can eliminate various impurities from your water, rendering it safe for all uses, including cooking, washing, and drinking.

It is common for manufacturers to sell whole house filtration systems designed specifically for well water. Often, these include functions not found in standard whole house filters.

The following is an explanation of how a well water filtering system works.

Pre-Filtration Stage

The pre-filtering stage usually focuses on solid particles such as sand, rust bits, and silt, which is accomplished by using a sediment filter.

Main Filtration

  • Many homes with well water require iron filters because excessive amounts of iron cause stains, discoloration, and harm to equipment.
  • Additionally, a carbon filter may remove pesticides and other pollutants from well water.
  • KDF systems are another prevalent form of water filtration used here. They remove certain chemicals and heavy metals.

Post-Filtration Stage

After being treated, well water may be passed through a post-filter to eliminate any leftover contaminants. The post-filtration stage is meant to cover any blind spots left from the two previous stages, ensuring your water is clean and safe to consume.

UV water purifiers are often used at this step as they can remove hazardous germs and work at peak efficiency when other physical particles have been removed.

The Different Types of Whole House Well Water Filters

Well water filtration systems are classified according to the toxins they remove. The following are some of the most common systems:

Filters for Fe, Mn, S

Oxidation is used to remove iron, manganese and sulfur.

Often, these systems include a backwash component that aids in keeping the filters clean and operating properly.

Filters for Sediment

Sediment filters remove the most visible well water pollutants. They’re made to eliminate physical contaminants like dirt, sand, and rust.

Depending on the number of impurities in your well, sediment filters should be replaced every couple of months.

Filter Systems Made of Carbon

Carbon-based filters remove chlorine, VOCs, pesticides, herbicides, etc. They can also remove gritty dirt and debris.

Kinetic Degradation Fluxion Filters

KDF filters are typically used in tandem with other types. They function by eliminating chlorine and heavy metals from water through a process known as redox (oxidation-reduction).

Bacteria and other pathogenic pollutants can also be controlled using KDF filters.[1]

UV Water Purifiers

UV water purifiers are incredibly effective at dealing with microorganisms, such as bacteria, protozoa and viruses. UV light damages the DNA of microbes, preventing them from reproducing.

However, UV systems do not physically remove any contaminants.

Water Softeners

water softeners and whole house water filters

In many cases, well water is hard due to its high mineral content. Although hard water is not inherently harmful, it might cause problems in your house’s plumbing and lead to build-up in filters.

Hard water may also cause dry skin and hair, and reduce the effectiveness of soap.

You could buy a water softener to avoid these problems. Water softeners function by exchanging hard minerals in well water for softer sodium through a process known as ion exchange.

Is a Well Water Filtration System Necessary?

Well water is more prone to pollution since it originates from the earth and, unlike city water, is not in any way treated to reduce the dangers of precipitation, bacteria, organism degradation – you name it.

So, yes, a well water filtration system is necessary in most cases.

Because the EPA does not regulate private wells, it is your obligation to ensure that your water is safe.

Why You Need to Have Your Well Water Tested

You can have your well water analyzed by a state-certified laboratory or hire a water testing firm. A thorough water test will identify your water’s physical, chemical, and biological conditions.

Water tests often look for contaminants such as E. coli and other bacteria. If you find bacteria in your water, you’ll have to act fast to avoid any health consequences.

Other tests are performed to look for nitrates, iron, lead, copper and other metals. These can also be dangerous, particularly to newborns and young children. And iron in water can cause rust-colored stains on your garments for example.

You should also have your water’s hardness and pH levels evaluated. Water with a high hardness level is difficult to clean with and can create many other problems. Low pH water can erode pipes. It can also provide a metallic flavor to your water.

How Frequently Should You Test?

While it is suggested to test your well water once a year, there are various circumstances in which you may need to test more frequently.

When these scenarios appear, the EPA suggests immediate testing:

  • If you notice any changes in your water quality
  • If there are known water problems in your area
  • Following environmental occurrences such as flooding and land disturbances
  • Following the repair or replacement of well components or pipes
  • When there is industrial or construction activity near your area

How to Select the Right Well Water Filter

When trying to select the right water filter for your well, there are various factors to consider:


First and foremost, you should have your well water checked because knowing what’s in it will make it easier to pick the ideal filtration system to remove those specific impurities.

For example, if your well water contains a high concentration of ferrous iron, you should look for an iron filter making use of oxidation.

The Size of Your Home

Your home’s flow rate will also determine the size of the required filtering equipment. A high flow rate necessitates a larger and therefore more expensive system. If you live in a smaller house you can go with a smaller-sized well water filter.

Understanding how your well pump operates will help you identify the flow rate. Aside from the amount of water used in your home, the flow rate is also affected by the well pump size.

Filter Replacements

collection of whole house water filters

Some filtering systems are simpler to maintain than others. Before purchasing, consider how frequently you’re willing to clean or replace filters and the expense of this.

After Sale Services

Lastly, don’t forget to look at the manufacturer’s warranties and customer service. A reputable company should provide at least a 1-year warranty on all parts.

They should also offer a responsive customer support service that you can quickly contact if you have any inquiries or issues with your system.

Is Well Water Harmful or Safe?

Because soil functions as a natural filter, groundwater is generally considered safe.

However, numerous additional factors, such as bad construction or obsolete components, might contaminate your well water.

Your well water will be safe if you correctly treat the issues and practice regular maintenance.


If you own a private well, you must install a water filtration system.

How a well water filtration system works exactly depends on its type. There are iron filters, sediment filters, carbon filters, etc.

The different types can be arranged to target all of the contamination issues you are facing.

Ideally, you have a pre-filtration stage, main filtration and a post-filtration stage.

Further Reading


Meet Jason Hollow

Jason Hollow 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.

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