Tap water may be reasonably healthy for many people, but that’s small comfort for those who don't want chlorine in their water - a common drawback in public water supplies - or, far more seriously, for individuals with compromised immunity or certain chronic illnesses. For these folks, a wide range of filters and purification methods are available to combat everything from chlorine to contamination by organisms and heavy metals.

 

entry continues below ↓

Water purification involves the use of filters, agents or exchangers to remove chemical or microbial contaminants from domestic water. These methods may be employed at the point of use, or they may be used to purify water throughout the house.

Purification differs from water softening, which removes dissolved minerals associated with water hardness - iron, manganese and calcium. For more information on this topic, see the entry, Water conditioner.

Purifiers range from simple, inexpensive countertop pitchers to faucet systems to permanently installed equipment covering parts of, if not the entire, house. Many pitchers use carbon filters and reverse osmosis to remove chlorine, microbes and heavy metals. Faucet and under-sink models may employ similar technologies.

Whole-house systems, the most sophisticated purifiers, can be designed to combat specific water contaminants - for those who can afford purchasing and maintaining them. Nevertheless, this technology is essential for those whose private well water may have one or more contaminants.

It’s advisable to have a sample of household water analyzed by a certified laboratory to determine whether any water hazards are present before committing to the purchase of a sophisticated purification system. Reputable dealers and contractors who install this equipment should offer this service before selling you a system.

We’ve prepared the table below to show methods that are effective in reducing or eliminating nine common contaminants.
 

	Arsenic	Bacteria, viruses	Cryptosporidium, giardia	Chlorine)	Lead	Nitrates	Pesticides	Radium	Radon
Adsorptive media	X			X
Aeration				X					X
Disinfection		X
Distillation	X	X	X	X	X	X		X
Absolute 1-micron filter			X
Carbon filter				X			X		X
Cyst re- moval filter			X
Ion exchange					X	X		X
Reverse osmosis	X	X	X	X	X	X		X
Ultraviolet light		X	X