No one system removes all possible contaminants and the various treatment technologies differ widely in their effectiveness in removing different classes of contaminants. For example, while activated carbon filters are efficient in removing organic compounds, pesticides, and lead, distillation effectively removes metals and microorganisms. Therefore, an important first step for the homeowner before any system is purchased is to have the drinking water analyzed. The county health department or a private laboratory can provide this analysis and public health officials can interpret these results to help the homeowner determine which treatment process is most appropriate.

No federal, state. or local regulations govern the manufacturing or use of home water treatment units. Many different brands are available in the marketplace. To ensure some level of quality and effectiveness, certification of treatment units is carried out by independent testing laboratories such as the National Sanitation Foundation NSF). Their insignia will be evident on the packaging or individuals can contact the NSF to find out if a particular product has been certified for the use intended. Also, the Water Quality Association (WQA), a trade association of manufacturers and distributors, offers voluntary validation standards and advertising guidelines to their members. Thus, the WQA seal of approval provides another indication of product quality.

To check on the certification or validation of a product, call the National Sanitation Foundation at 313-769-8010 or the Water Quality Association at 312-369-1600.