Nearly half of the U.S. population relies on groundwater as a drinking water source. That’s more than 140 million people, and about 45 million of that group draw groundwater through private wells — sources particularly vulnerable to contamination since they aren’t subjected to the same standards as public water utilities. Groundwater quality is important to the nation, to say the least.That’s where recently released data from the U.S. Geological Survey comes into the picture. As part of its ongoing National Water-Quality Assessment, the agency sampled 5,000 wells across the country between 1988 and 2001. About one-third of those wells were sampled
