The US Geological Survey is near the midpoint of a complex undertaking to survey the quality of the nation’s largest drinking-water resource. From 2012 to 2023, the USGS is assessing groundwater throughout the country through extensive sampling. The latest results from five regional aquifers have just become available.
About half of the nation’s population relies on groundwater for drinking water. As the nation’s population grows, the need for high-quality drinking-water supplies becomes even more urgent. The Survey has identified 68 principal or regionally extensive aquifers across the nation that can be used as a source of drinking water . Groundwater pumped from these aquifers provides nearly 50 percent of the nation’s drinking water. Twenty of these principal aquifers account for about 75 percent of groundwater pumped for public supply and 85 percent of the groundwater pumped for domestic supply. These 20 principal aquifers are being intensively evaluated by the USGS National Water-Quality Assessment Project. Summary results for five principal aquifers are recently completed and are now available online.