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.
Featured: Deciphering the U.S. urban stream pesticide signature
A new USGS study reports that 16 dissolved pesticides were consistently detected in small streams in 16 urban centers across five regions of the United States.
Featured: Potential pesticide toxicity to aquatic life is widespread
A new USGS study of pesticides in U.S. rivers and streams reports that, on average, 17 pesticides were detected at least once at the 74 river and stream sites sampled 12 to 24 times per year during 2013–2017.
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.
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
Water-Quality Benchmarks for Contaminants
Groundwater Age
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.
- Overview
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.
Featured: Deciphering the U.S. urban stream pesticide signature
A new USGS study reports that 16 dissolved pesticides were consistently detected in small streams in 16 urban centers across five regions of the United States.
Featured: Potential pesticide toxicity to aquatic life is widespread
A new USGS study of pesticides in U.S. rivers and streams reports that, on average, 17 pesticides were detected at least once at the 74 river and stream sites sampled 12 to 24 times per year during 2013–2017.
Quick LinksLooking 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.
Sources/Usage: Public Domain.From left: Aquatic sampling during Southeast Stream Quality Assessment; velocity measurement at Truckee River, Nevada; wrestling with cages of fathead minnows in Goodwater Creek, Missouri, during high flow. 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.
Sources/Usage: Public Domain.From left: measuring groundwater salinity in Georgia; collecting groundwater samples for laboratory analysis in Florida; sampling shallow groundwater wells for an agricultural land-use study in Georgia; collecting groundwater samples in Nevada. 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.
Sources/Usage: Public Domain.From left: Installing shallow groundwater wells at ephemeral ponds; the Alapaha River , a "losing" stream at low flow; marking groundwater seeps. (Credit: Alan Cressler, USGS) 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.
Sources/Usage: Public Domain.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 ContaminationCONTAMINANTS 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 ResearchRELATIONS 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 coresPROCESSES
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.
- Science
Learn more about some of the research associated with the National Water Quality Assessment project.
Filter Total Items: 33Agricultural Contaminants
About 40 percent of the land in the United States is used for agriculture, and agriculture supplies a major part of the our food, feed, and fiber needs. Agricultural chemicals move into and through every component of the hydrologic system, including air, soil, soil water, streams, wetlands, and groundwater.Chloride, Salinity, and Dissolved Solids
All natural waters contain some dissolved solids (salinity) from contact with soils, rocks, and other natural materials. Too much, though, and dissolved solids can impair water use. Unpleasant taste, high water-treatment costs, mineral accumulation in plumbing, staining, corrosion, and restricted use for irrigation are among the problems associated with elevated concentrations of dissolved solids.Arsenic and Drinking Water
Arsenic is a naturally occurring element, but long-term exposure can cause cancer in people. There has been a substantial amount of research done to address arsenic in groundwater and drinking-water supplies around the country. The USGS studies local and national sources of arsenic to help health officials better manage our water resources.Coal-Tar-Based Pavement Sealcoat, PAHs, and Environmental Health
Sealcoat is the black, viscous liquid applied to many asphalt parking lots, driveways, and playgrounds in North America to protect and enhance the appearance of the underlying asphalt. Coal-tar-based pavement sealcoat is a potent source of polycyclic aromatic hydrocarbon (PAH) contamination in urban and suburban areas and a potential concern for human health and aquatic life.Pesticides and Water Quality
Pesticides are chemicals designed to kill pests, including insects (insecticides), weeds (herbicides), and fungi (fungicides). The USGS assesses the occurrence and behavior of pesticides in streams, lakes, and groundwater and the potential for pesticides to contaminate our drinking-water supplies or harm aquatic ecosystems.Mercury
Mercury is a potent neurotoxin that can affect the human nervous system. Eating fish contaminated with mercury can cause serious harm to people and wildlife.Metals and Other Trace Elements
Metals, metalloids, and radionuclides all are trace elements that occur naturally in the Earth's crust. In small quantities many trace elements are essential for health in all living organisms, but some trace elements can be toxic or cause cancer, and some can bioaccumulate. The USGS investigates where and how trace elements make their way into our Nation's surface water and groundwater.Corrosivity
Corrosivity describes how aggressive water is at corroding pipes and fixtures. Corrosive water can cause lead and copper in pipes to leach into drinking water and can eventually cause leaks in plumbing. Surface water and groundwater, both sources of drinking water, can potentially be corrosive.Streamflow Alteration
Humans, just like aquatic organisms, need water. Flood control, urban infrastructure, irrigation of agriculture, and myriad other ways we manage water affect the natural flow of streams and rivers. How do the ways we manage land and water affect the natural patterns of streamflow that ecosystems depend on?Radionuclides
Many people might be surprised to learn that drinking-water sources, especially groundwater, can contain radioactive elements (radionuclides). Radionuclides in water can be a concern for human health because several are toxic or carcinogenic. Other radionuclides are useful tools for determining the age of groundwater in an aquifer or of sediment deposited at the bottom of a water body.Water-Quality Benchmarks for Contaminants
How does the water quality measure up? It all depends on what the water will be used for and what contaminants are of interest. Water-quality benchmarks are designed to protect drinking water, recreation, aquatic life, and wildlife. Here you’ll find links to some of the most widely used sets of water, sediment, and fish tissue benchmarks and general guidance about their interpretation.Groundwater Age
The age of groundwater is key in predicting which contaminants it might contain. There are many tracers and techniques that allow us to estimate the age—or mix of ages—of the groundwater we depend on as a drinking water supply. - Data
- Multimedia
- Publications
- Web Tools
- Software
- News
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.