Water Filter Systems
American Water Facts
Americans spend billions of dollars each year on home water filter systems. According to the Water Quality Association, more than four out of 10 Americans use a home water treatment unit. These units range from simple pitchers costing less than $20 to sophisticated reverse osmosis units costing hundreds of dollars.
Some people use a home water treatment unit to improve the taste of their tap water. Others treat their water because of health concerns. While EPA does not endorse specific units, the Agency does set and enforce national standards for the tap water provided by public water systems.
Drinking water can reasonably be expected to contain at least small amounts of some contaminants. As long as those contaminants are at levels no higher than EPA standards, the water is considered safe to drink for healthy people.
People with severely weakened immune systems or other specific health conditions, or those concerned about specific contaminants present in local drinking water, may wish to further treat their water at home or purchase high quality bottled water.
Before purchasing a home water treatment unit, consider local water quality, cost and maintenance of the unit, product performance, and certifications to make sure that the unit will meet your needs.
The following information briefly describes how different types of home water filter systems work. For details, read information that accompanies the product and look for independent certification of manufacturers’ claims.
Different units remove different contaminants or classes of contaminants from the water. Sophisticated units may use multiple technologies to remove several types of contaminants and to provide backup protection in case one treatment fails.
Water filter systems can either be free-standing, attached to a tap, plumbed in with a dedicated faucet (also called a point-of-use device) connected to a refrigerator’s water and ice dispensing system; or centrally attached to treat all water entering a house (a point-of-entry device).
For most contaminants, a point-of-use device is effective for treating only the water that is consumed. However, some contaminants, such as radon, disinfection byproducts, and some organic chemicals, easily turn into gases and may pose a risk when inhaled, such as when showering.
A point-of-entry device can reduce concentrations of these contaminants and others that cause aesthetic problems such as scaling, staining, or odor.
Faucet & Sink Filters
These water filter systems generally use the same technologies as their pour-through pitcher counterparts.Some filters use fabrics, fiber,or ceramic screening to physically remove contaminants. The most common types use a molded block of activated carbon.
These filters are effective at improving the taste of tap water, and some will also reduce lead, protozoan cysts, and many other contaminants. Like filter pitchers, shelf lives and specific contaminants removed vary so read the label and instructions carefully.
Distillers heat water to the boiling point, and then collect the water vapor as it condenses, killing disease-causing microbes and leaving most chemical contaminants behind.Contaminants that easily turn into gases, such as gasoline components or radon, may remain in the water unless the system is specifically designed to remove them.
Distilled water may taste flat to some people because the water’s natural minerals and dissolved oxygen often have been removed.
Reverse Osmosis Units
Reverse osmosis units force water through a semi-permeable membrane under pressure, leaving contaminants behind. Reverse osmosis units use approximately three times as much water as they treat, but they are effective in eliminating all disease causing organisms and most chemical contaminants.
Water softeners use a cation exchange resin, regenerated with sodium chloride or potassium chloride, to reduce the amount of hardness (calcium, magnesium) in the water. The hardness ions in the water are replaced with sodium or potassium ions. Ion exchange water softeners simultaneously remove radium and barium while removing water hardness.