Using Granular Activated Carbon to Filter Water Contaminants

Granulated activated carbon is a common filter material used in water filtration systems. It’s a proven way to remove certain organic chemicals from water. GAC filters are also effective at removing contaminants that give an objectionable odor or taste to drinking water, like hydrogen sulfide or chlorine.


While it is effective on a number of organic chemicals, others like iron and nitrate are not attracted to the carbon and as a result are not removed. That’s why GAC filters are often used in other water filtration systems like reverse osmosis or green sand. 


What Is A Granulated Active Carbon Filter?

GAC is made from organic materials which have a high carbon content like coconut shells or coal. The material is heated in an oxygen-free chamber to activate the surface of the carbon, which is why these filters are often referred to as “charcoal” filters. The activated carbon better removes certain chemicals that are dissolved in water by trapping the chemicals in the carbon.
When choosing to install GAC water filtration systems in your home, it’s important to have a thorough water analysis done. The types and levels of contaminants, as well as your family’s average water use are important factors to consider when sizing a system.


Like all water filtration systems, proper installation and regular maintenance is important to maintain the highest function. With GAC filters, the carbon becomes saturated and no longer effective after a certain length of service. How often filters must be changed is also determined by the level of contaminants present and amount of water used. Some filters last for several years if water use and contaminants levels are low. If levels and use are higher, more frequent filter changes are advised.


Types Of GAC Or Granulated Active Carbon Filtration Systems


There are two basic types of water filtration systems available to homeowners and GAC filters are used in both. A whole-house or "Point of Entry" system takes water from your well and treats it before it enters your home’s plumbing system. Typically a POE system treats all of the water outlets, faucets, washing machine, and dishwasher, but excludes outdoor faucets to help prolong the life of the GAC filter.  POE systems usually consist of 2 filtering cylinders that treat the water in sequence. The second filter designed to further clean the water of contaminants that may have passed through the first.



The second type of system is called "Point of Use." Point of use systems are installed just before the faucet where people get their water. One common system consists of an independent faucet exclusively for treated water usually located next to the kitchen faucet for example. Another example of POU filters that use GAC are the pitcher filters commonly sold in grocery stores. GAC filters are also included in many refrigerators that dispense drinking water and ice.


If you’re considering adding a water treatment system in your home and are not sure if a GAC system is right for you, contact a qualified well water contractor. They can give you all of your options, along with the installation costs, and can help you to get your water tested to determine what type of system is the best for your family. A water treatment system is a smart investment in the health of your loved ones! Contact the well water experts at Skillings & Sons for a water test, water treatment or well servicing estimate.