HMD, ND

The function of the carbon is to act as a type of catalyst that removes certain substances from the water by chemical reaction. Carbons are good for removing chlorine (by turning it into chloride ions) and any organics present; organics contribute to tastes and smells. Once downstream of a carbon filter, any protection that the chlorine offered against bacterial growth is gone, so it is recommended to use the water straight away, and not to store it for any long period of time.

Coconut carbon is quite adequate for this task, as are carbons from other sources.

Carbons will do very little towards removal of dissolved metals.

Carbon filters should be either backwashed in the case of a granulated material, or replaced in the case of a cartridge material, at intervals recommended by the manufacturer.

For further protection of the user from bacteria, equipment that uses ultraviolet light [UV] can be installed immediately upstream of the point of consumption. While not removing any bacteria from the water, the UV does ensure that the bacteria are dead. For further information it is best to contact a number of manufacturers.

Guest reply #1 generally correct other than how Chlorines and Chlorides interact with activated carbon.

Before moving forward with building a system the make-up of you water needs to be determined. What is the SDI (Silt Density index) of the feed water, what is the hardness of your water (measured in grains), what is the free and total chlorine levels and what is the total average water usage for the whole house each day or month. Once these questions are answered then a proper system can be assembled unless of course you are willing to spend 20K on a state-of-the art system not counting upkeep costs.

The average home without hard water can normally get by with a 20 inch 10 micron filter for the whole house and install 10 carbon filters at points of use where the water is to be used for drinking or cooking. Cost would be around $150-$2000 depending on how much of the installation you do yourself. The filters if changed every month would ballpark around $10-$20.