How To Filter Well Water (4 Proven Systems + Common Contaminants)

If you own a home or are considering purchasing a home with a well, you likely have some concerns about the water quality. You may be wondering how to filter well water so it is safe to drink.

You can filter water from a well by using whole-home filtration systems, under-sink or counter filtration systems, refrigerator filters, or even basic ‘plug-in’ filters for your faucet or showerhead. Before setting up a well water filtration system, be sure to get your well water tested so that you know which kind of filter will work best.

Read on to learn more about well water filtering systems and the most common water contaminants!

Why should you filter well water?

Well water is cool and refreshing. It is also higher in minerals and nutrients. Groundwater is typically clean because soil acts as a natural filter. As surface water percolates through the different layers of the soil, bacteria, viruses, and chemicals are filtered out. In a perfect world, this would be enough to ensure drinkable water. Right?

Well water must often be filtered to rid it of contaminants. The average household uses many synthetic substances that are known to pollute ground and surface water. Environmental issues like flooding and nearby digging can affect well water quality. Purification removes harmful substances so the water is ready to drink and use in food preparation.

How to filter well water
Well water often needs to be filtered to rid it of contaminants.

How to filter well water

How do you know you need to filter your well water, and how do you go about it? Isn’t boiling enough? Boiling is a natural way to purify water, but uber time-consuming. Water filtration systems are basically hands-free once installed.

Determine if you need to filter your well water by doing a water test. If your water contains germs, then it’s time to choose the right filter system, install the filter, and do regular maintenance to make sure it is performing as it should.

Step 1: Perform a water quality test

The Environmental Protection Agency (EPA) makes sure our public drinking water is safe. However, it is up to the homeowner to make sure their private well water is safe to consume. Testing is easy and inexpensive, with home kits available for under $30.

Some states have programs through county health departments that will send an environmentalist to collect the sample and take it in for testing.

Testing kits can detect heavy metals, nitrates, chemicals, and bacteria. They can also test the pH. The EPA recommends yearly testing, or anytime there are land changes close to the well. Just because your water is clear doesn’t mean it’s free of toxins. Toxins dissolve and are undetectable to the naked eye.

Step 2: Choose a filtration system

Filtration systems come in different styles and price points. Once your water has been tested and you have the results, you can choose the filter that works best for the specific contaminants and your budget.

Water filtration systems include whole-house systems, under-the-sink and counter systems, refrigerator filters, and plug-in sink filters. These vary in price and complexity. A whole-house system filters the water as it comes into the house. The other systems only filter individual water lines and faucets.

Let’s dissect the most common types of filtration systems:

  • Whole-house filters
  • Under-the-sink & Counter filters
  • Refrigerator filters
  • Faucet/shower filters
Well-water filter system options
Well-water filtration systems

Whole-house filters

Whole-house filters perform just as the name implies. They are installed where the main water line comes into the house. The water is filtered before it travels throughout the house. This is an excellent option if you want drinking, bathing, and cooking water to be filtered.

This is the most expensive system, but it is highly customizable to your needs. Whole-house systems commonly purify and filter water via ultraviolet light and/or carbon. The UV method kills harmful bacteria and germs. Carbon filters are rockstars at removing chemicals, pesticides, and excessive amounts of chlorine.

Whole-house systems can also remove sediment, soften water, and improve pH levels.

Under-the-sink & counter filters

If you don’t want to spend big bucks on a whole-house system, under-the-sink and counter filters are partial systems that are more budget-friendly. Under-the-sink models are connected to the sink plumbing. Counter models are placed on top of the counter and connected to the faucet.

These types of filters are easy to install if you are DIY-inclined. These systems commonly use reverse osmosis (RO) to filter out contaminants. RO uses a semi-permeable membrane to filter out heavy metals, radionuclides, organic compounds, and fluoride from well water. It does more than just eliminate the contaminants, it also improves the flavor of your drinking water because it filters out impurities that can interfere with taste.

Refrigerator filters

If you are only concerned with the quality of your ice or drinking water, a refrigerator filter will fit the bill. Depending on your water’s contaminants, you will need to purchase a filter that is certified to remove those specific issues. Refrigerator filters come in different sizes and shapes to fit specific appliance models. They are easy to screw into place.

The National Sanitation Foundation (NSF) labels water filters with a number so you know they meet removal standards. For example, filters labeled “NSF 42” effectively remove odor, sediment, and chlorine. Those labeled “NSF 53” can also remove heavy metals and pesticides.

Faucet & shower filters

Faucet and shower filters are filters that are attached to the actual sink faucet or showerhead. They are relatively inexpensive and easy to install. These filters can be purchased at most big box or hardware stores under brand names like Brita, PUR, and Culligan.

Carbon filters are used to remove chlorine, some heavy metals, and chemicals. It is important to know what is in your water, so you can choose the best filter. According to the CDC, these filters don’t remove everything. While some are excellent at improving taste, they might not be as effective at removing chemicals. Look for the NSF standards on the box to see what you are buying.

Step 3: Install the filtration system

Once you’ve chosen the right filter for your water issues, it’s time to install it. A whole-house system requires professional installation. Under-the-sink or counter filters can be installed by the homeowner, depending on comfort level. Refrigerator, faucet, and showerhead filters are simple to install.

Step 4: Conduct regular maintenance

Filters do require regular maintenance. In most cases, it is recommended to replace the actual filtering mechanism annually. Refrigerator and faucet filters often have a light that will come on when it is time to change the filter.

Common well water contaminants that need to be filtered out

While well water is known for its great-tasting water, it is possible for it to become contaminated because of the land and area around it. Pets, livestock, run-off from construction or chemical sites, and the condition of the soil around the well can affect your water.

The most common well water contaminants are microorganisms, heavy metals, nitrites/nitrates, organic chemicals, radionuclides, and fluoride. Water testing can identify any problems and help you choose the correct water filter system for your needs.

  • Microorganisms
  • Heavy metals
  • Nitrites and nitrates
  • Organic chemicals
  • Radionuclides
  • Fluoride
Is your well water contaminated?
Is your well water contaminated?


Microorganisms include viruses, bacteria, and parasites that primarily come from human and animal waste. If you have a septic system, you may want to do regular inspections to ensure it is not causing pollution to the groundwater.

Drinking water that is contaminated with microorganisms can result in all kinds of waterborne diseases (e.g., harmful algal blooms, hot tub rash, norovirus infection, swimmer’s ear, swimmer’s itch, dysentery, cholera, etc.).

Heavy metals

Heavy metals from industries, municipal waste disposals, natural minerals, and household plumbing can leak into the drinking water. Some of the heavy metals that are known to be found in drinking water include selenium, copper, lead, cadmium, antimony, chromium, and arsenic.

If you consume water that is contaminated with heavy metals, you might develop acute toxicity in your liver and kidneys or suffer from intestinal damage. Diseases like anemia and cancer have also been linked to heavy metals in drinking water.

Nitrites and nitrates

Most nitrogenous material in natural water typically converts to nitrate, so any source of combined nitrogen (mostly ammonia and organic nitrogen) should be thought of as a potential nitrate source.

The main source of organic nitrates is human waste and livestock manure. Ammonium nitrate and potassium nitrate from fertilizers are the primary inorganic nitrates that can contaminate your well. High levels of nitrites and nitrates in drinking water can contribute to acquired methemoglobinemia.

Organic chemicals

What do you do with expired medicines? Many people just flush them down the toilet, oblivious of the effects that can have on the environment.

If you have a septic tank, expired pharmaceuticals will not be broken down by the bacteria in the tank. This means they end up in the leach field and percolate into the groundwater. Other household organic chemicals that could pollute water include paints, dyes, pesticides, petroleum products, sealants, disinfectants, and petroleum products. Consuming water that is contaminated with organic chemicals may result in damaged circulatory and nervous systems.

Other known effects include damage to the liver, kidney, and reproductive systems.


Radionuclides are radioactive contaminants that can be found in water. They can appear naturally or as a result of human activity (e.g. mining of uranium, production of nuclear power, and coal mining).

Radionuclides can contaminate well water through wastewater seepage and clouding. As radionuclides break down, they cause radiation, releasing dangerous toxins that can cause kidney failure and cancer.


Fluoride not only occurs naturally, but it is also common practice for municipals to add it to water because fluoride plays an important role in strong teeth and bone formation. However, when in excessive amounts, fluoride can result in skeletal or dental fluorosis.

The CDC recommends a maximum fluoride count of 2 milligrams per liter.

What’s the difference between filtration and purification?

When choosing a well-water system, you may see both “filtration” and “purification” listed among product details. Are they the same thing? No!

Filtration refers to the act of filtering particles or bacteria with a physical barrier. Purification rids the water of unseen contaminants like viruses and chemicals through processes. Carbon filters are an example of a filtration device. Reverse osmosis or ultraviolet light are purification methods.

It might be necessary to both filter and purify your well water. This is why a water quality test is so important. It will help you choose the correct system or systems for your water’s unique makeup.

Summary of how to filter well water

Well water has a reputation for being clean, cool, and refreshing. It’s a good idea to test your well water to make sure it doesn’t contain any harmful or unpleasant contaminants.

When potential issues are detected, whole-house, under-the-sink/counter, refrigerator, faucet, and showerhead filtration systems can eliminate everything from excessive fluoride to microorganisms.


What is the best way to filter water from a well?

Choosing a filter system for your well water takes water testing and basic knowledge of the filter systems available. You can choose between whole-house, partial under-the-sink, counter, refrigerator, or faucet/showerhead filtration systems. Some systems are better at dealing with specific contaminants than others.

Does all well water need to be filtered?

Water testing will determine if your well water needs to be filtered. If harmful contaminants are found, you should filter.

How can I naturally purify my well water?

You can naturally purify well water by boiling it for 3 minutes. However, this method is very time-consuming.

How much does a whole house filtration system cost?

Whole-house filtration systems can cost $800-4,000+ plus installation and maintenance costs.

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