Water Center


Date of this Version



United States government work


Document abstract

Secure, reliable, and sustainable water resources are fundamental to the Nation’s food production, energy independence, and ecological and human health and well-being. Indications are that at any given time, water resources are under stress in selected parts of the country. The large-scale development of groundwater resources has caused declines in the amount of groundwater in storage and declines in discharges to surface water bodies (Reilly and others, 2008). Water supply in some regions, particularly in arid and semiarid regions, is not adequate to meet demand, and severe drought intensifies the stresses affecting water resources (National Drought Mitigation Center, the United States Department of Agriculture, and the National Oceanic and Atmospheric Association, 2015). If these drought conditions continue, water shortages could adversely affect the human condition and threaten environmental flows necessary to maintain ecosystem health.

In support of the national census of water resources, the United States Geological Survey (USGS) completed the national brackish groundwater assessment to provide updated information about brackish groundwater as a potential resource to augment or replace freshwater supplies (Stanton and others, 2017). Study objectives were to consolidate available data into a comprehensive database of brackish groundwater resources in the United States and to produce a summary report highlighting the distribution, physical and chemical characteristics, and use of brackish groundwater resources. This assessment was authorized by section 9507 of the Omnibus Public Land Management Act of 2009 (42 U.S.C. 10367), passed by Congress in March 2009. Before this assessment, the last national brackish groundwater compilation was completed in the mid-1960s (Feth, 1965). Since that time, substantially more hydrologic and geochemical data have been collected and now can be used to improve the understanding of the Nation’s brackish groundwater resources.

Data abstract

Brackish groundwater (BGW), defined for this assessment as having a dissolved-solids concentration between 1,000 and 10,000 milligrams per liter, is an unconventional source of water that may offer a partial solution to current (2016) and future water challenges. In support of the National Water Census, the USGS has completed a BGW assessment to gain a better understanding of the occurrence and characteristics of BGW resources of the United States as an alternative source of water. Analyses completed as part of this assessment relied on previously collected data from multiple sources, and no new data were collected. One of the most important contributions of this assessment was the creation of a database containing chemical data and aquifer information for the known quantities of BGW in the United States. Data were compiled from single publications to large datasets and from local studies to national assessments, and includes chemical data on the concentrations of dissolved solids, major ions, trace elements, nutrients, radionuclides, and physical properties of the resource (pH, temperature, specific conductance). This database represents data from a compilation of water-quality samples from 100,000+ (major-ions data) to 300,000+ (dissolved-solids data) groundwater wells across the continental United States, Alaska, Hawaii, Puerto Rico, the US Virgin Islands, Guam, and American Samoa. The data are published here as an ESRI geodatabase with a point feature class and associated attribute table, and also as non-proprietary comma-separated value table. It was not possible to compile all data available for the Nation, and data selected for this investigation were mostly limited to larger datasets that were available in a digital format.