Home Water Treatment Units

There are several types of home water treatment units available, each using a different technology and achieving different results. Selecting the wrong one can result in a water supply that is dangerously compromised, whereas selecting the right one can transform water from distasteful to sparkling clear. Each homeowner must assess their own situation, decide on the results desired, and make a careful selection. 

Filtration systems:
Some home water treatment units work by filtration, in which the water passes through a filtering medium to remove substances. This category is subdivided into physical and activated carbon filters.

Physical filters are good for homes receiving water from wells with a high level of grit and natural sediments. They can also extract asbestos fibers from water, and some units will remove disease-causing bacteria. However, a physical filtration unit will not remove all microorganisms, and is not adequate treatment for microbiologically unsafe water.

Activated carbon filters are good for removing organic chemicals, but are not adequate against inorganic substances such as metals or salts. They can also let some disease-causing microorganisms pass through. There are activated carbon filters for removing lead from water, but homeowners should make sure they are getting a unit specifically made for this.

Ultraviolet systems:
These home water treatment units use ultraviolet light to treat water. In Class A systems the goal is to disinfect, while Class B systems remove heterotrophic bacteria and inactivate viruses. Where water has a foul smell and taste from bacterial growth, an ultraviolet system can often remedy the problem. They will not remove chemical contaminants, spores or cysts.

Reverse osmosis systems:
In reverse osmosis home water treatment units, water passes through a membrane to remove unwanted substances. This works well for removing inorganic contaminants such as salts, metals, nitrates, asbestos and unwanted minerals. It does not remove microorganisms well, and is not recommended for treating microbiologically unsafe water. 

Distillation systems:
These home water treatment units work by evaporating water and re-condensing it. This removes inorganic contaminants such as salts, metals, minerals and asbestos. It does not remove all chemicals, as some will evaporate and condense with the water. Some microorganisms can also survive the process, though most will be removed or killed. Homeowners should be aware that distillation systems will add to their power bill.

Water softening systems:
Hard water is caused by magnesium and calcium ions. A water softening system uses a cation exchange resin to replace unwanted ions with sodium or potassium ions. The problems caused by hard water include poor foaming of soaps and detergents, irritation to skin and hair and fading of textiles. While the cation exchange system does not protect against other contaminants, it is a good remedy for hard water.