Every time a faucet is turned on in your home, water rushes through a network of unseen pipes, driven by pressure so you can use it to wash your hands, do the dishes, or fill a glass. When you dry your hands off or raise the cool glass of water to your lips, you are probably not thinking of water pollution. That, you think, is vats of dark oil spilling into the ocean. It is piles of trash floating atop the surface of swamps and strangling wildlife. It is cyanobacteria producing toxic algal blooms. And yet water pollution is much closer than one might think.
Water can be polluted as it traverses through the pipes in people’s homes. Homes with lead service lines, pipes that connect the home to the main water line, can cause lead to be present in drinking water. Homes without lead service lines can still have brass or chrome-plated brass faucets, galvanized iron pipes, or plumbing with lead solder. Lead enters drinking water when the plumbing corrodes, because of a reaction between water and the plumbing that occurs when the water has high acidity or low mineral content. 
To combat contamination in drinking water, Congress passed the Safe Drinking Water Act (SDWA), which allowed the U.S. Environmental Protection Agency (EPA) to set standards for drinking water quality.  For lead, the EPA has set the maximum contaminant level goal at zero because lead can bioaccumulate in the body and is harmful to human health even at low exposure levels. In addition, the EPA issued the Lead and Copper Rule under the authority of the SDWA, which requires utilities to make water less corrosive to plumbing. 
For young children, infants, and fetuses, lead is particularly harmful. In children, low levels of lead in the blood have been linked to damage to the nervous system, behavior and learning problems, slowed growth, and impaired hearing. Ingestion of lead can also cause seizures, coma, and death. While drinking water isn’t the only source of lead exposure for children, the EPA estimates that water can make up about twenty percent of a person’s total exposure to lead.  In adults, exposure to lead can lead to cardiovascular and kidney problems.
Although not many houses built after 1986 contain lead service lines, there are steps to take if you think your water might have lead. Water can be tested through water utilities, and a “point-of-use” filter can be used. Cold water doesn’t corrode pipes as much as hot water, and the pipes can be flushed before drinking by taking a shower or doing the dishes. 
Ultimately, although the threat of lead contaminating drinking water has subsided in recent years, it’s a reminder that the world is more connected than we think. Even small choices can have an impact far greater than we might imagine.