Estimated equivalent population using groundwater for public supply domestic use in the conterminous U.S. 2010, hydrogeologic mapping units, and wells used (ver. 2.0, March 2023)

These datasets map the estimated population using public supply drinking water (both groundwater and surface water) using two methods: the census enhanced method (CEM) evenly distributes the population across populated census blocks, and the urban land-use enhanced method (ULUEM) distributes the population only to certain urban land use designations. (See the six Estimated equivalent population using public supply datasets). The estimated number of people using public supply was also computed by county (See Table of estimated county population using public supply dataset).
In addition, a polygon dataset was created for the conterminous U.S. that identifies 177 unique Hydrogeologic Mapping Units (HMUs). (See Community public supply based Hydrogeologic Mapping Units dataset). The HMUs do not overlap, but they can delineate areas where stacked hydrogeologic regions (HRs) contribute drinking water from below the surface. HRs are water-bearing geologic regions identified as either a principal aquifer (PA) or secondary hydrogeologic region (SHR). Within each HMU, community public supply wells were used to determine the proportion of each HR that is providing groundwater to the HMU. Over a five-year period, these wells were assigned to an HR from which they sourced their water from (See the Public supply groundwater wells dataset).