Berkey Water Purification Process

What is a Berkey Water Filter System?

The Berkey water filter is an effective, freestanding water purification system designed to provide drinking water for everyday use or in case of emergency. It doesn't require electricity because it is gravity-fed. Water from almost any source can be poured into the upper chamber of the unit, and by the time it reaches the lower chamber it is the purest, healthiest water you can drink: Berkey Water.

What is included in a Berkey order?

How do Berkey Filters Work?

The Black Berkey Filters, sometimes also called the Black Berkey Purification Elements are the true powerhouses of the Berkey system. They work on three different principles: absorption, adsorption, and microfiltration. These methods are combined and blended to produce a unique filter process.

How does a Berkey work?



The first line of defense against contaminants is the material that the Black Berkey Filters are made of. Each cylindrical filter is composed of a formulation of more than six different media types, all constructed into a very compact matrix containing millions of microscopic pores. The microscopic topography of the surface of the filter elements contains millions of tiny holes that let water pass through. These holes are so minute that pollutants physically cannot pass through them.  Furthermore, these micropores pass through the filter shell in convoluted twists and turns known as a “tortuous path,” further ensnaring the tiniest pathogenic bacteria, cysts, parasites, sediment and sedimentary minerals. 

This part of the Berkey purification process is similar to the legacy filters like the old Royal Doulton or the British Berkefeld. 

Unfortunately, in modern times, there are more contaminants to deal with than germs alone. Agricultural and industrial activity can contaminate the water with pollutants like heavy metals and volatile chemicals that require more than just microfiltration.

What does Berkey remove?

How Berkey Filters Water


The technology Berkey uses for this step in the filtering process is ion exchange. This process is similar to leaving an opened box of baking soda open in the fridge to absorbs the funny smells. Heavy metals ions (chromium, lead or copper molecules) are extracted from the water through an ion exchange process where they are attracted to and transformed by electrically bonding to the media. Ions are molecules that are unbalanced--the number of electrons does not equal the number of protons. Molecules want to restore balance so they are attracted to other molecules that would equal out their charge. The Black Berkey filters are loaded with ions that attract contaminant molecules. Those molecules are absorbed and permanently bonded to the filter, never entering the drinking water in the bottom chamber of the Berkey.


Adsorption works to create an ionic barrier similar to surface tension. The barrier spanning between the micropores blocks water contaminants, such as submicron viruses, that are smaller than the pore size itself. Berkey filters take advantage of viruses' electrostatic charge and pulls them in against the walls of the tunnels in the “tortuous path" of the filter. Similar to static cling, it holds tiny viruses against the surfaces in the filter and never lets go. Berkey has the prestigious classification of water purifier, not just a water filter, due to its ability to remove viruses. Other water filters cannot without the use of adverse chemicals like iodine or chlorine. 

Exposure Time

Finally, because of the gravity flow nature of a Berkey, molecules in water take several minutes to pass through the filter elements, whereas molecules in other filtration systems pass through in fractions of a second. The longer contact time between the water molecules and the filter media, provides much greater removal rates of harmful water contaminates not obtainable through conventional pressurized water filtration methods. 

Berkey water is better water.

The results of independent lab testing of the Berkey permit it to be qualified as a water purifier as opposed to just a water filter. To be called a water filter, a product must remove pathogenic bacteria to a level of 99.99%. The higher standard of water purifier requires a removal of 99.9999% of pathogenic bacteria.

Independent test results show that Berkey water meets NSF/ANSI standard 53 for reductions in heavy metals, like mercury and lead, disinfectant byproducts, parasites like Cryptosporidium and Giardia, VOCs like dichlorobenzene, trichloroethylene, and MTBE as well as radon and pesticides.

Berkey Water Filter Systems incorporate several different scientific methods to produce unmatched drinking water quality. Powerful technology and easy to use. All that it takes to operate is simply pour water into the upper chamber of a Berkey Water Filter System. The long filter life produces purified drinking water for pennies a gallon. The processes of microfiltration, adsorption and absorption continue to work effectively for years and years.

Learn more about water purification.

Berkey Filtration Test Results

Check out the specifications and performance outcomes.

Does Berkey Remove Minerals?

Learn more about beneficial minerals in your water.

Do Berkey Filters Change Your pH Level

Depending on your water, Berkey may change the pH level