During hydrocarbon production, water is typically co-produced from the geologic formations producing oil and gas. Understanding the composition of these produced waters is important to help investigate the regional hydrogeology, the source of the water, the efficacy of water treatment and disposal plans, potential economic benefits of mineral commodities in the fluids, and the safety of potential sources of drinking or agricultural water. The U.S. Geological Survey National Produced Waters Geochemical Database v2.3 is an updated compilation of geochemical and related information for water from oil and gas wells in the United States. It includes identification and location information, well descriptions, dates, rock properties, physical properties of the water, inorganic chemistry, organic chemistry, and isotopes. Disclaimer for Provisional Database The data you have secured from the U.S. Geological Survey (USGS) National Produced Waters Geochemical Database v2.3 are provisional and subject to revision. The data are released on the condition that neither the USGS nor the United States Government may be held liable for any damages resulting from their authorized or unauthorized use.