NAWQA—Tracking and Forecasting the Nation's Water Quality
What’s in the water? And is water quality getting better or worse?
Surface-Water Quality and Ecology
Drinking water, irrigation, recreation, habitat—learn about water quality of our streams and rivers, how it’s changing, and why that matters
Groundwater Quality
Do you drink water from a well? Find out about the quality of this invisible resource used for drinking water by almost half the Nation’s population.
Water-Quality Topics
Read about USGS water-quality science on a range of topics, from pesticides to PAHs, from radionuclides to redox
New Water-Quality Directions
The USGS Water Resources Mission Area is updating current water programs to meet 21st century water-resource challenges.
Our surface water, groundwater, and aquatic ecosystems are priceless resources, used by people across the Nation for drinking, irrigation, industry, and recreation. The National Water-Quality Assessment (NAWQA) Project is a leading source of scientific data and knowledge for development of science-based policies and management strategies to improve and protect our water resources.
Quick Links
Looking for data? Maps? Use these links to quickly access some of the most frequently visited USGS web pages on water quality.
In 1991, Congress established the National Water-Quality Assessment (NAWQA) Project to address where, when, why, and how the Nation's water quality has changed, or is likely to change in the future, in response to human activities and natural factors. Since then, NAWQA has produced scientific data and knowledge that is used by national, regional, state, and local agencies to develop science-based policies and management strategies to improve and protect water resources used for drinking water, recreation, irrigation, energy development, and ecosystem needs. A prominent feature of NAWQA is the development of long-term consistent and comparable information on streams, rivers, ground water, and aquatic systems. The NAWQA Project is designed to answer these questions:
- What is the current condition of our Nation's streams, rivers, and groundwater?
- How are these conditions changing over time?
- How do natural features and human activities affect these conditions, and where are those effects most pronounced?
NAWQA Water-Quality Research
SURFACE WATER AND ECOLOGY
Water Quality and Ecology of Small Streams (RSQA)
The Regional Stream Quality Assessment (RSQA) is studying the relations between stressors (chemical and physical) and stream ecology (fish, algae, and aquatic invertebrates) at small streams in five large regions of the United States. Users can access an online mapping tool to compare water quality at small streams across a region, see scorecards that summarize stream health at each stream site, and download data for hundreds of chemical compounds.
Water Quality in the Nation's Streams and Rivers: Current Conditions and Long-Term Trends
Knowing the current water-quality conditions of our rivers and streams and where those conditions have improved or deteriorated is critical information for resource managers and the public. An online water-quality tracking tool shows graphs of pesticides, nutrients, and sediment in streams, and users can download data for a streams and rivers across the country; the tool is updated annually. The online water-quality trends mapping tool allows users to visualize trends in water chemistry (nutrients, pesticides, sediment, carbon, and salinity) and aquatic ecology (fish, invertebrates, and algae).
SPARROW modeling: Estimating nutrient, sediment, and dissolved solids transport
SPARROW (SPAtially Referenced Regression On Watershed attributes) models estimate the amount of a contaminant transported from inland watersheds to larger water bodies by linking monitoring data with information on watershed characteristics and contaminant sources. Users can explore relations between human activities, natural processes, and contaminant transport using interactive mappers.
GROUNDWATER
Groundwater Quality: Current Conditions and Changes Through Time
Scientists are characterizing groundwater quality in principal aquifers, the primary source of the Nation's groundwater used for drinking. Concentrations of inorganic constituents, such as arsenic and nitrate, and organic constituents, such as pesticides and volatile organic compounds, are compared to benchmarks established for the protection of human health. Users can access an online tool to see how concentrations of pesticides, nutrients, metals, and organic contaminants in groundwater are changing during decadal periods across the Nation, and see in real time how chemical properties of groundwater at some sites are fluctuating.
Groundwater Quality: Predictions for Unmonitored Areas
Groundwater hydrologists are developing statistical models that predict where a contaminant is likely to occur in groundwater and at what concentration. These models extrapolate groundwater quality in areas and at depths where groundwater has not yet been sampled. Users can see predicted contaminant concentrations in map view, and—for some aquifers—in 3-D.
SURFACE WATER/GROUNDWATER INTERACTION
Groundwater/Surface-Water Interaction
Surface water and groundwater are intimately connected and are constantly interacting. The Integrated Watershed Studies team is quantifying how water and chemicals move between the landscape, streams and rivers, and groundwater. Learn how the quantity and quality of surface water and groundwater are likely to change in response to changes in climate, land use, and best management practices.
NAWQA — The First Two Decades
From 1991-2001, the NAWQA Project conducted interdisciplinary assessments, including water chemistry, hydrology, land use, stream habitat, and aquatic life, and established a baseline understanding of water-quality conditions in 51 of the Nation's river basins and aquifers, referred to as Study Units.
From 2001-2012, NAWQA focused on specific water-quality topics of national interest, such as pesticides, nutrients, and aquatic ecology, as well as continuing to monitor and assess 42 of the Study Units.
► Learn about the first two decades of NAWQA research and access information and publications about the quality of the Nation's surface-water and groundwater resources.
How do we do it?
Find methods used by NAWQA to assesses the current quality of our surface water and groundwater.
► Documentation on water-quality sample collection methods developed by NAWQA.
Explore Related Topics on Water-Quality Research
RELATIONS BETWEEN LAND USE AND WATER QUALITY
Urban Land Use and Water Quality
Agricultural Contamination
CONTAMINANTS IN WATER
Arsenic and Drinking Water
Chloride, salinity, and dissolved solids
Emerging contaminants (including pharmaceuticals and hormones)
Mercury
Metals and Other Trace Elements
Nutrients and Eutrophication
National Atmospheric Deposition Program (NADP)
Pesticides and Water Quality
Coal-Tar-Based Pavement Sealcoat, PAHs, and Environmental Health
Radionuclides
Sediment-associated contaminants
Volatile organic compounds (VOCs) (including MTBE)
DRINKING WATER ISSUES
Corrosivity
Domestic (private) supply wells
Public-supply wells
Drinking-water taste and odor
Water-Quality Benchmarks for Contaminants
Drinking Water and Source Water Research
RELATIONS TO AQUATIC LIFE
Stream ecology
Mercury
Streamflow Alteration
NWQP Research on Harmful Algal Blooms (HABs)
TRENDS IN WATER QUALITY
Water-quality trends
Water-quality trends from lake sediment cores
PROCESSES
Oxidation/Reduction (Redox)
Groundwater Age
► Confused by some of the water-quality terms? Find the definitions and explanations you're looking for in the Water-Quality Glossary.
Learn more about some of the research associated with the National Water Quality Assessment project.
Acid Rain
Agricultural Contaminants
Chloride, Salinity, and Dissolved Solids
Arsenic and Drinking Water
Coal-Tar-Based Pavement Sealcoat, PAHs, and Environmental Health
Pesticides and Water Quality
Mercury
Metals and Other Trace Elements
Corrosivity
Streamflow Alteration
Radionuclides
Groundwater Age
Web applications and downloadable data related to NAWQA water-quality research.
Changes in anthropogenic influences on streams and rivers in the conterminous U.S. over the last 40 years, derived for 16 data themes
Generalized lithology of the conterminous United States
Estimating the presence of paved surface parking lots in the conterminous U.S. from land use coefficients for 1974, 1982, 1992, 2002, and 2012
Laboratory Quality-Control Data Associated with Groundwater Samples Collected for Hormones and Pharmaceuticals by the National Water-Quality Assessment Project in 2013-15
Third-party performance assessment data encompassing the time period of analysis of groundwater samples collected for hormones and pharmaceuticals by the National Water-Quality Assessment Project in 2013-15
Environmental and Quality-Control Data Collected by the USGS National Water-Quality Assessment Project for Hormones and Pharmaceuticals in Groundwater Used as a Source of Drinking Water Across the United States, 2013-15
Water-quality trends and trend component estimates for the Nation's rivers and streams using Weighted Regressions on Time, Discharge, and Season (WRTDS) models and generalized flow normalization, 1972-2012
Changes in anthropogenic influences on streams and rivers in the conterminous U.S. over the last 40 years, derived for 16 data themes
Natural Monthly Flow Estimates for the Conterminous United States, 1950-2015
Datasets and metadata for estimates of nitrate loads and yields from groundwater to streams in the Chesapeake Bay watershed based on land use and geology
Code, data, executables, and other information used to run Unit Flows in Networks of Channels (UFINCH) - A method for simulating unit and daily flows in networks of channels described by NHDPlus using continuous flow data at U.S. Geological Survey streamg
Data Release for Metamodeling and Mapping of Nitrate Flux in the Unsaturated Zone and Groundwater, Wisconsin, USA
Geochemistry of Sediment and Associated Leachates from Samples near the Old Yuma Mine, AZ
The NAWQA project publishes reports that describe water-quality and ecological conditions; whether conditions are changing over time; and how natural features and human activities affect these conditions.
The most recent publications and selected national-scale reports are listed here.
Flow modification in the Nation’s streams and rivers
Pesticides and pesticide degradates in groundwater used for public supply across the United States: Occurrence and human-health context
Machine learning predictions of pH in the Glacial Aquifer System, Northern USA
Factors affecting nitrate concentrations in stream base flow
Geochemistry and age of groundwater in the Williston Basin, USA: Assessing potential effects of shale-oil production on groundwater quality
Nitrate in streams during winter low‐flow conditions as an indicator of legacy nitrate
Prioritizing river basins for intensive monitoring and assessment by the US Geological Survey
Groundwater-quality and select quality-control data from the National Water-Quality Assessment Project, January through December 2016, and previously unpublished data from 2013 to 2015
Fluoride occurrence in United States groundwater
Biofilms provide new insight into pesticide occurrence in streams and links to aquatic ecological communities
The relation of geogenic contaminants to groundwater age, aquifer hydrologic position, water type, and redox conditions in Atlantic and Gulf Coastal Plain aquifers, eastern and south-central USA
Groundwater quality in the Biscayne aquifer, Florida
Groundwater quality in the Columbia Plateau basaltic-rock aquifers, northwestern United States
Interactive mappers and web applications related to NAWQA water-quality research.
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.
Our surface water, groundwater, and aquatic ecosystems are priceless resources, used by people across the Nation for drinking, irrigation, industry, and recreation. The National Water-Quality Assessment (NAWQA) Project is a leading source of scientific data and knowledge for development of science-based policies and management strategies to improve and protect our water resources.
Quick Links
Looking for data? Maps? Use these links to quickly access some of the most frequently visited USGS web pages on water quality.
In 1991, Congress established the National Water-Quality Assessment (NAWQA) Project to address where, when, why, and how the Nation's water quality has changed, or is likely to change in the future, in response to human activities and natural factors. Since then, NAWQA has produced scientific data and knowledge that is used by national, regional, state, and local agencies to develop science-based policies and management strategies to improve and protect water resources used for drinking water, recreation, irrigation, energy development, and ecosystem needs. A prominent feature of NAWQA is the development of long-term consistent and comparable information on streams, rivers, ground water, and aquatic systems. The NAWQA Project is designed to answer these questions:
- What is the current condition of our Nation's streams, rivers, and groundwater?
- How are these conditions changing over time?
- How do natural features and human activities affect these conditions, and where are those effects most pronounced?
NAWQA Water-Quality Research
SURFACE WATER AND ECOLOGY
Water Quality and Ecology of Small Streams (RSQA)
The Regional Stream Quality Assessment (RSQA) is studying the relations between stressors (chemical and physical) and stream ecology (fish, algae, and aquatic invertebrates) at small streams in five large regions of the United States. Users can access an online mapping tool to compare water quality at small streams across a region, see scorecards that summarize stream health at each stream site, and download data for hundreds of chemical compounds.
Water Quality in the Nation's Streams and Rivers: Current Conditions and Long-Term Trends
Knowing the current water-quality conditions of our rivers and streams and where those conditions have improved or deteriorated is critical information for resource managers and the public. An online water-quality tracking tool shows graphs of pesticides, nutrients, and sediment in streams, and users can download data for a streams and rivers across the country; the tool is updated annually. The online water-quality trends mapping tool allows users to visualize trends in water chemistry (nutrients, pesticides, sediment, carbon, and salinity) and aquatic ecology (fish, invertebrates, and algae).
SPARROW modeling: Estimating nutrient, sediment, and dissolved solids transport
SPARROW (SPAtially Referenced Regression On Watershed attributes) models estimate the amount of a contaminant transported from inland watersheds to larger water bodies by linking monitoring data with information on watershed characteristics and contaminant sources. Users can explore relations between human activities, natural processes, and contaminant transport using interactive mappers.
GROUNDWATER
Groundwater Quality: Current Conditions and Changes Through Time
Scientists are characterizing groundwater quality in principal aquifers, the primary source of the Nation's groundwater used for drinking. Concentrations of inorganic constituents, such as arsenic and nitrate, and organic constituents, such as pesticides and volatile organic compounds, are compared to benchmarks established for the protection of human health. Users can access an online tool to see how concentrations of pesticides, nutrients, metals, and organic contaminants in groundwater are changing during decadal periods across the Nation, and see in real time how chemical properties of groundwater at some sites are fluctuating.
Groundwater Quality: Predictions for Unmonitored Areas
Groundwater hydrologists are developing statistical models that predict where a contaminant is likely to occur in groundwater and at what concentration. These models extrapolate groundwater quality in areas and at depths where groundwater has not yet been sampled. Users can see predicted contaminant concentrations in map view, and—for some aquifers—in 3-D.
SURFACE WATER/GROUNDWATER INTERACTION
Groundwater/Surface-Water Interaction
Surface water and groundwater are intimately connected and are constantly interacting. The Integrated Watershed Studies team is quantifying how water and chemicals move between the landscape, streams and rivers, and groundwater. Learn how the quantity and quality of surface water and groundwater are likely to change in response to changes in climate, land use, and best management practices.
NAWQA — The First Two Decades
From 1991-2001, the NAWQA Project conducted interdisciplinary assessments, including water chemistry, hydrology, land use, stream habitat, and aquatic life, and established a baseline understanding of water-quality conditions in 51 of the Nation's river basins and aquifers, referred to as Study Units.
From 2001-2012, NAWQA focused on specific water-quality topics of national interest, such as pesticides, nutrients, and aquatic ecology, as well as continuing to monitor and assess 42 of the Study Units.
► Learn about the first two decades of NAWQA research and access information and publications about the quality of the Nation's surface-water and groundwater resources.
How do we do it?
Find methods used by NAWQA to assesses the current quality of our surface water and groundwater.
► Documentation on water-quality sample collection methods developed by NAWQA.
Explore Related Topics on Water-Quality Research
RELATIONS BETWEEN LAND USE AND WATER QUALITY
Urban Land Use and Water Quality
Agricultural Contamination
CONTAMINANTS IN WATER
Arsenic and Drinking Water
Chloride, salinity, and dissolved solids
Emerging contaminants (including pharmaceuticals and hormones)
Mercury
Metals and Other Trace Elements
Nutrients and Eutrophication
National Atmospheric Deposition Program (NADP)
Pesticides and Water Quality
Coal-Tar-Based Pavement Sealcoat, PAHs, and Environmental Health
Radionuclides
Sediment-associated contaminants
Volatile organic compounds (VOCs) (including MTBE)
DRINKING WATER ISSUES
Corrosivity
Domestic (private) supply wells
Public-supply wells
Drinking-water taste and odor
Water-Quality Benchmarks for Contaminants
Drinking Water and Source Water Research
RELATIONS TO AQUATIC LIFE
Stream ecology
Mercury
Streamflow Alteration
NWQP Research on Harmful Algal Blooms (HABs)
TRENDS IN WATER QUALITY
Water-quality trends
Water-quality trends from lake sediment cores
PROCESSES
Oxidation/Reduction (Redox)
Groundwater Age
► Confused by some of the water-quality terms? Find the definitions and explanations you're looking for in the Water-Quality Glossary.
Learn more about some of the research associated with the National Water Quality Assessment project.
Acid Rain
Agricultural Contaminants
Chloride, Salinity, and Dissolved Solids
Arsenic and Drinking Water
Coal-Tar-Based Pavement Sealcoat, PAHs, and Environmental Health
Pesticides and Water Quality
Mercury
Metals and Other Trace Elements
Corrosivity
Streamflow Alteration
Radionuclides
Groundwater Age
Web applications and downloadable data related to NAWQA water-quality research.
Changes in anthropogenic influences on streams and rivers in the conterminous U.S. over the last 40 years, derived for 16 data themes
Generalized lithology of the conterminous United States
Estimating the presence of paved surface parking lots in the conterminous U.S. from land use coefficients for 1974, 1982, 1992, 2002, and 2012
Laboratory Quality-Control Data Associated with Groundwater Samples Collected for Hormones and Pharmaceuticals by the National Water-Quality Assessment Project in 2013-15
Third-party performance assessment data encompassing the time period of analysis of groundwater samples collected for hormones and pharmaceuticals by the National Water-Quality Assessment Project in 2013-15
Environmental and Quality-Control Data Collected by the USGS National Water-Quality Assessment Project for Hormones and Pharmaceuticals in Groundwater Used as a Source of Drinking Water Across the United States, 2013-15
Water-quality trends and trend component estimates for the Nation's rivers and streams using Weighted Regressions on Time, Discharge, and Season (WRTDS) models and generalized flow normalization, 1972-2012
Changes in anthropogenic influences on streams and rivers in the conterminous U.S. over the last 40 years, derived for 16 data themes
Natural Monthly Flow Estimates for the Conterminous United States, 1950-2015
Datasets and metadata for estimates of nitrate loads and yields from groundwater to streams in the Chesapeake Bay watershed based on land use and geology
Code, data, executables, and other information used to run Unit Flows in Networks of Channels (UFINCH) - A method for simulating unit and daily flows in networks of channels described by NHDPlus using continuous flow data at U.S. Geological Survey streamg
Data Release for Metamodeling and Mapping of Nitrate Flux in the Unsaturated Zone and Groundwater, Wisconsin, USA
Geochemistry of Sediment and Associated Leachates from Samples near the Old Yuma Mine, AZ
The NAWQA project publishes reports that describe water-quality and ecological conditions; whether conditions are changing over time; and how natural features and human activities affect these conditions.
The most recent publications and selected national-scale reports are listed here.
Flow modification in the Nation’s streams and rivers
Pesticides and pesticide degradates in groundwater used for public supply across the United States: Occurrence and human-health context
Machine learning predictions of pH in the Glacial Aquifer System, Northern USA
Factors affecting nitrate concentrations in stream base flow
Geochemistry and age of groundwater in the Williston Basin, USA: Assessing potential effects of shale-oil production on groundwater quality
Nitrate in streams during winter low‐flow conditions as an indicator of legacy nitrate
Prioritizing river basins for intensive monitoring and assessment by the US Geological Survey
Groundwater-quality and select quality-control data from the National Water-Quality Assessment Project, January through December 2016, and previously unpublished data from 2013 to 2015
Fluoride occurrence in United States groundwater
Biofilms provide new insight into pesticide occurrence in streams and links to aquatic ecological communities
The relation of geogenic contaminants to groundwater age, aquifer hydrologic position, water type, and redox conditions in Atlantic and Gulf Coastal Plain aquifers, eastern and south-central USA
Groundwater quality in the Biscayne aquifer, Florida
Groundwater quality in the Columbia Plateau basaltic-rock aquifers, northwestern United States
Interactive mappers and web applications related to NAWQA water-quality research.
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.