How to Purify Well Water for Drinking

Because there are many types of well water, there are also many ways to purify well water.

The best way to purify well water for drinking is always to use the correct water treatment technique for the contaminants present in the water. Learning how to test your well water comes first if you don’t have that information.

Some well water contaminants are identifiable by their appearance, taste, or smell.

For example, sulfur is a commonly occurring groundwater metal that creates a foul-smelling gas that many people compare to rotten eggs.

Other contaminants are invisible to the senses and cannot be identified without water testing or by reading resources about a body of water.

As a result, it’s often difficult to know how to apply the correct water treatment method to well water. If you’re unsure about the contaminants present in your well, either commission a drinking water test or use the maximum number of treatment types that you have available.

Illustration of full water glass with water droplet

Purification vs filtration

Well water treatments are divided into two categories: purification and filtration.

Purification treatments modify, disinfect, or deactivate contaminants in well water to render them safe to drink.

Filtration treatments remove contaminants from the water supply or reduce them to safe levels, using a well water filtration system.

Well water purification techniques

Chlorine disinfection

Chlorine is a universal water purification method. By adding this chemical to well water in safe amounts, parasites, bacteria, and viruses are destroyed. It is often used for treating coliform in well water.

How to use chlorine disinfection on well water: Often referred to as “shock chlorination”, the most common way to use chlorine to purify well water is to periodically flush the well system through with a large quantity of chlorine.

Shock chlorination tends to last between six months and a year.

Ultraviolet (UV) purification

The use of ultraviolet purification on well water is growing in popularity. UV purifiers work by shining a high-intensity light through a water supply that disrupts the DNA of bacteria and viruses. While the pathogens remain inside the water supply, they no longer present a risk to health.

How to use ultraviolet purification on well water: UV bulbs need to be sealed inside a perfectly dark casing to effectively purify well water. Installing UV purifiers is a delicate process and is best left to a professional.

Every month that a UV purifier is in operation, the bulb can lose between five and ten percent of its efficiency per month. As a result, UV bulbs should be replaced on a yearly basis.

Well water filtration techniques

Micron filtering

A micron filter is the most simple type of well water filtration. It contains a semi-permeable material filled with tiny pores that allow water to pass through while catching undissolved particles of a certain size. Micron filters are an effective way to reduce the level of sand, silt, dirt, dust, or rust in well water.

Most micron filters have the ability to filter undissolved contaminants at larger than, 5, 10, 20, 0r 20 microns, depending upon the filter media rating.

How to use a micron filter on well water: Most well owners install micron filters at an early point in a home's plumbing. This helps protect other, more delicate filtration stages from large particles of dirt and debris.

Micron filters use screens that are either replaceable or cleanable. Keeping a micron filter screen clear of debris is essential for proper filter functioning.

Carbon filtering

Granular activated carbon is another common type of filter media that can be used to reduce levels of dissolved organic contaminants in well water. Organic contaminants include disinfectant byproducts, agricultural chemicals, decaying plant matter, and industrial or urban runoff.

Carbon filters contain a cartridge of highly-pure ground charcoal with an extensive surface area. Activated carbon is able to attract and bind organic contaminants to its surface through a process called adsorption. When the surface of the carbon is saturated, the filter cartridge must be replaced.

How to use a carbon filter on well water: Carbon filters come in many different formats, including pitcher filters, faucet filters, undersink filters, and whole house filters. When using carbon filtration to treat well water, most homes choose a whole house filtration tank, as this treats water for all outlets.

KDF filtering

KDF filters operate on a similar principle to carbon filters, in that they pass the water supply through a granulated filter media. KDF media is often composed of metals like copper or manganese dioxide, which have an oxidizing effect on dissolved metal contaminants.

Oxidizing dissolved metals encourages them to take on an insoluble form, allowing them to be more efficiently filtered from well water. Common well water contaminants that can be filtered using a KDF device include iron and sulfur.

How to use a KDF filter on well water: KDF filters are cartridge-style filters, which means that they need to be replaced every 6-12 months, once the media inside becomes saturated. For filtering iron, many well owners combine a KDF filter with a micron filter.

Injection (oxidization) filtering

Like KDF filters, the main purpose of an injection filter is to oxidize dissolved metals in a water supply, in order to make them easier to remove. Injection filters do this via two main water: by injecting are or by injecting an oxidizing chemical such as chlorine.

Most injection filters contain a green-sand filtration media designed to capture the oxidized metals once they have passed through the injection tank. Many consider air injection to be the best iron filter for well water as they capture more iron and have fast flow rates.

How to use an injection filter on well water: Both air injection and chlorine injection filters can be effective on well water with high amounts of iron, sulfur, manganese, and some other dissolved metals.

When using an air injection filter, it's important to ensure that the injected air pockets do not encourage the growth of iron bacteria.

Reverse osmosis (RO) filtering

Reverse osmosis filters are an advanced type of filtration system that utilizes pumps to force water through a semi-permeable membrane with small (sometimes microscopic) pores. This method allows reverse osmosis filters to remove a large variety of contaminants, including dissolved chemicals and metals, sediment, and microorganisms

How to use a RO system on well water: Due to their intense filtration method, reverse osmosis greatly restricts water flow rate. As a result, well owners usually install a water storage tank alongside an RO system. This allows a reserve of water to be collected for use throughout the day.