Read the full story from the Associated Press.
Though estimates vary, roughly 53 million U.S. residents — about 17% of the population — rely on private wells, according to a study conducted in part by Environmental Protection Agency researchers. Most live in rural areas. But others are in subdivisions near fast-growing metro regions or otherwise beyond the reach of public water pipes.
While many private wells provide safe water, the absence of regulation and treatment afforded by larger municipal systems may expose some users to health risks, from bacteria and viruses to chemicals and lead, studies have found.
Risks are elevated after flooding or heavy rainfall, when animal and human feces, dirt, nutrients such as nitrogen and other contaminants can seep into wells. And experts say the threat is growing as the warming climate fuels more intense rainstorms and stronger and wetter hurricanes.