How dangerous levels of lead in the Tap Water

By far the biggest threat in tap water is lead. Ingestion of lead causes a wide variety of serious health problems. Children who drink lead-tainted water often sustain irreversible brain damage, resulting in reduced IQ scores, short attention span and other mental problems.

(These problems are also common among infants born to mothers who drink lead-tainted water while pregnant.) In adult lead poisoning can cause kidney damage, high blood pressure and brittle bones. It can also cause brain damage, although adult neurological tissue is less sensitive to lead than children's neurological tissue.

Exposure of skin to lead-containing water, during a bath or shower, for example is not considered dangerous.