Drip Drop Water Talk

Separating the sales pitch from science

What’s in my Brita filter?

Brita Filter 3 pack 2015-07-15 v2

Brita filters have become incredibly popular in the United States.  Available as faucet mounted filters or as cartridge filters for pitchers, these filters are an easy means of removing aesthetic contaminants from drinking water.  Two primary technologies exist inside of the filter: granular activated carbon and ion exchange resin.

The granular activated carbon (GAC) is derived from coconut shells and its primary purpose is to remove any taste and odor from the water.  Most people do not find the chlorine and chloramines that are added to drinking water by the water treatment plants to control the growth of microorganisms very palatable.  GAC is able to easily remove these contaminants as well as any disinfection by-products that are produced when the chlorine comes into contact with organic matter in the water.  As coconut carbon has a high surface area due to its microporous structure, the GAC is able to adsorb a high amount of contaminants from water.  Once all the adsorption sites are taken up by organics, the GAC will cease to function as intended.

The ion exchange (IX) resin is mixed into the GAC in order to remove heavy metals such as copper, cadmium, mercury, and lead.  These metals have a positive charge in water and are naturally attracted to the cation IX resin.  In other applications using IX such as water softening, the resin is recharged and is able to be reused over and over.  The Brita filter is designed to be disposable, and the IX resin inside is not meant to be recharged.  Once all the exchange sites are occupied by positively charged ions, the IX resin will also cease to work properly.

The Brita filters are a decent means of producing good tasting drinking water.  However, their capacity is limited and it’s one of the most expensive methods of polishing drinking water.  At its current price of $14.88 for a set of three replacement filters, each gallon of water through the filter will cost $0.12.  This is higher than the cost of using other types of filters (such as countertop or undersink) but still much cheaper than buying bottled water.

(Pictured at top: Brita filter 3 pack on Amazon, uploaded by Brita)


Friday Five 2015-07-17


  1. Veronica

    Kristen, what type of home filter is the most economical for is effectiveness? And how does it stand up to well water?

    • Kristen

      It really depends on what you’re trying to get out of the water. Are you trying to treat a whole home, just the cold line, just the hot line, or just a branch of water for drinking?

  2. Soak your new filter in water for 15-20 minutes to make sure that the carbon is saturated, just as you would any store-bought replacement filter. Once done, your DIY Brita replacement is ready to go. Place it into your dispenser and enjoy purified water.

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