National Water Quality Program
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The National Water Quality Program provides an understanding of water-quality conditions; whether conditions are getting better or worse over time; and how natural features and human activities affect those conditions.
Featured Study: Insights into changes in chloride in streams
A joint USEPA-USGS study finds that integrating water-quality sampling approaches can provide insight into changing chloride concentrations in U.S. streams and rivers.
Learn moreFeatured Study: Potential lead solubility in groundwater
About one-third of more than 8,300 wells tested across the U.S. had groundwater with chemical characteristics that could cause lead, if present in plumbing, to leach into tap water at levels above the EPA Action Level.
Learn MoreNews
Groundwater age-dating simplified
A new USGS report documents a simple method to classify groundwater age as premodern (recharged before 1953), modern (recharge in 1953 or later), or a mix of the two. The method—tritium-based age classification, or TBAC—requires just a single measurement of tritium, along with knowledge of sample date and location...
Isotopic tracers in fish in Northeast provide clue to mercury sources
Isotopes of mercury in fish can indicate the source of that mercury, reports a new study from the USGS Regional Stream Quality Assessment.
USGS National Water Quality Laboratory protocols effective at minimizing false-positive pesticide results
A new analysis of USGS National Water Quality Laboratory (NWQL) quality-control protocols finds that “false-positive” and “false negative” results—reporting that a compound is present in a sample when it is not or that a compound is not present when it is—are minimal.
Publications
Hydrocarbons in upland groundwater, Marcellus Shale Region, Northeastern Pennsylvania and Southern New York, USA
Water samples from 50 domestic wells located <1 km (proximal) and >1 km (distal) from shale-gas wells in upland areas of the Marcellus Shale region were analyzed for chemical, isotopic, and groundwater-age tracers. Uplands were targeted because natural mixing with brine and hydrocarbons from deep formations is less common in those areas...
McMahon, Peter B.; Lindsey, Bruce D.; Conlon, Matthew D.; Hunt, Andrew G.; Belitz, Kenneth; Jurgens, Bryant; Varela, Brian Estimating domestic well locations and populations served in the contiguous U.S. for years 2000 and 2010
Domestic wells provide drinking water supply for approximately 40 million people in the United States. Knowing the location of these wells, and the populations they serve, is important for identifying heavily used aquifers, locations susceptible to contamination, and populations potentially impacted by poor-quality groundwater. The 1990 census was...
Johnson, Tyler D.; Belitz, Kenneth; Lombard, Melissa Assessing water-quality changes in U.S. rivers at multiple geographic scales using results from probabilistic and targeted monitoring
Two commonly used approaches for water quality monitoring are probabilistic and targeted. In a probabilistic approach like the US Environmental Protection Agency’s National Rivers and Streams Assessment, monitoring sites are selected using a statistically representative approach. In a targeted approach like that used by many monitoring...
Sprague, Lori A.; Mitchell, Richard M; Pollard, Amina I.; Falcone, James A.