Homeowners and other individuals can take steps to insure the safety of their drinking water, Harris said, whether they live in urban areas with municipal water systems or in rural areas with water wells or other water sources. Contact the local health department to find out how to test your own water if it does not come from a public water system. The local health department will have information on testing private water wells. Know what kind of water pipes are in your home. Older residences built before 1988 may have lead water pipes or pipes that have been welded together with lead solder.
Some homes have copper pipes.
Both these metals can be absorbed into water that has been sitting in the pipes. If the home has lead or lead-soldered pipes, when the inside faucets have been shut off for a while perhaps overnight or for several days clear the pipes by letting the cold water flow until you can feel the temperature change. This makes the water safer for cooking or drinking because it flushes out water that may have absorbed lead or copper from the pipes. Instead, use cold tap water and heat it on the stove. Improperly used or disposed pesticides could leach into surface or ground water, and contaminate the local water supply.