Approximately 23 million U.S. citizens rely on their own private drinking water supplies. Most of these supplies are drawn from ground water through wells, but some households also use water from streams or cisterns. These households must take special precautions to ensure the protection and maintenance of their drinking water supplies. Private water supplies should be tested annually for nitrate and coliform bacteria to detect contamination problems early. They should be tested more frequently and for more potential contaminants, such as radon or pesticides, if a problem is suspected.
Many laboratories are available to test water quality.
EPA may be available from your local or state public health department. Some local health departments also test private water for free. Phone numbers for your local, county, or state health department are available under the government listings in your phone book. Testing for other contaminants will be more expensive. For example, testing for pesticides or organic chemicals may cost from several hundred to several thousand dollars.