Arsenic in domestic well water could affect 2 million people in the US

Clean drinking water can be easy to take for granted if your home taps into treated water sources. But more than 44 million people in the U.S. get their water from private domestic wells, which are largely unregulated. Of those, a new report estimates that about 2 million people could be exposed to high levels of naturally occurring arsenic in their water.
Geology News — ScienceDaily