One in every five samples of groundwater used as a source
for drinking contains at least one contaminant at a level of concern for human
health, according to a new U.S. Geological Survey report.
About 115 million people—more than one-third of the Nation’s
population—rely on groundwater for drinking water, and the need for
high-quality drinking-water supplies is becoming more urgent as the Nation’s
USGS scientists assessed water quality in source (untreated)
water from 6,600 wells in regionally extensive aquifers that supply most of the
groundwater pumped for the Nation’s drinking water, irrigation, and other uses.
The new USGS reports highlight how geology, hydrology, geochemistry, and
chemical use affect the concentrations of individual contaminants in
Regional summaries of where and why groundwater is
vulnerable to contamination now are available for the following aquifers and
These reports and the associated water quality data are
Additional information on the USGS National Water-Quality
Assessment Program’s groundwater quality activities for the next decade is