What’s in your groundwater? Learn about groundwater quality in the Principal Aquifers of nine regions across the United States in informative circulars filled with figures, photos, and water-quality information.
Groundwater is our invisible, vital resource—more than 75 billion gallons are pumped each day, and 155 million people rely on groundwater for drinking water. Although groundwater is a safe, reliable source of drinking water for millions of people nationwide, high concentrations of some chemical constituents can pose potential human-health concerns. Some of these contaminants come from the rocks and sediments of the aquifers themselves, and others are chemicals that we use in agriculture, industry, and day-to-day life.
When groundwater supplies are contaminated, millions of dollars can be required for treatment so that the supplies can be usable. Contaminants in groundwater can also affect the health of our streams and valuable coastal waters. By knowing where contaminants occur in groundwater, what factors control contaminant concentrations, and what kinds of changes in groundwater quality might be expected in the future, we can ensure the availability and quality of this vital natural resource in the future.
Based on thousands of samples collected from 1991 to 2010, the National Water-Quality Assessment Project has created informative circulars on water quality and the factors that affect it for each of nine regions, comprising 20 Principal Aquifers—regionally extensive aquifers that supply groundwater for drinking, irrigation, and other uses. The results for the Nation are summarized in a single circular. Samples were collected from 6,600 public-supply, domestic (private), and monitoring wells, and analyzed for a wide range of contaminants and constituents, including pesticides, nutrients, and radionuclides. Explanations of the findings presented in these circulars improve our understanding of the natural and human factors that affect the occurrence of contaminants in the Nation’s groundwater.
Learn more about USGS research on groundwater.
Major Findings
- Contaminants from geologic or manmade sources were a potential human-health concern in one of every five wells sampled in the parts of aquifers used for drinking water;
- Differences in geology, hydrology, geochemistry, and chemical use explain how and why aquifer vulnerability and concentrations of contaminants vary across the Nation;
- Changes to groundwater flow have also altered groundwater quality;
- Our actions today are determining groundwater quality for decades to come.
Click on the "Related Science" tab to find out more about our Nation's groundwater quality.
Follow the links below to the web pages below to learn about more USGS science on groundwater quality.
National Water-Quality Assessment (NAWQA)
Groundwater Quality—Current Conditions and Changes Through Time
Rapid Fluctuations in Groundwater Quality
Predicting Groundwater Quality in Unmonitored Areas
- Overview
What’s in your groundwater? Learn about groundwater quality in the Principal Aquifers of nine regions across the United States in informative circulars filled with figures, photos, and water-quality information.
Groundwater is our invisible, vital resource—more than 75 billion gallons are pumped each day, and 155 million people rely on groundwater for drinking water. Although groundwater is a safe, reliable source of drinking water for millions of people nationwide, high concentrations of some chemical constituents can pose potential human-health concerns. Some of these contaminants come from the rocks and sediments of the aquifers themselves, and others are chemicals that we use in agriculture, industry, and day-to-day life.
When groundwater supplies are contaminated, millions of dollars can be required for treatment so that the supplies can be usable. Contaminants in groundwater can also affect the health of our streams and valuable coastal waters. By knowing where contaminants occur in groundwater, what factors control contaminant concentrations, and what kinds of changes in groundwater quality might be expected in the future, we can ensure the availability and quality of this vital natural resource in the future.
Based on thousands of samples collected from 1991 to 2010, the National Water-Quality Assessment Project has created informative circulars on water quality and the factors that affect it for each of nine regions, comprising 20 Principal Aquifers—regionally extensive aquifers that supply groundwater for drinking, irrigation, and other uses. The results for the Nation are summarized in a single circular. Samples were collected from 6,600 public-supply, domestic (private), and monitoring wells, and analyzed for a wide range of contaminants and constituents, including pesticides, nutrients, and radionuclides. Explanations of the findings presented in these circulars improve our understanding of the natural and human factors that affect the occurrence of contaminants in the Nation’s groundwater.
Learn more about USGS research on groundwater.
Sources/Usage: Public Domain.Regional Assessments of Principal Aquifers Major Findings
- Contaminants from geologic or manmade sources were a potential human-health concern in one of every five wells sampled in the parts of aquifers used for drinking water;
- Differences in geology, hydrology, geochemistry, and chemical use explain how and why aquifer vulnerability and concentrations of contaminants vary across the Nation;
- Changes to groundwater flow have also altered groundwater quality;
- Our actions today are determining groundwater quality for decades to come.
Click on the "Related Science" tab to find out more about our Nation's groundwater quality.
- Science
Follow the links below to the web pages below to learn about more USGS science on groundwater quality.
National Water-Quality Assessment (NAWQA)
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.Groundwater Quality—Current Conditions and Changes Through Time
Is groundwater the source of your drinking water? The USGS is assessing the quality of groundwater used for public supply using newly collected data along with existing water-quality data. Learn more about this invisible, vital resource so many of us depend on.Rapid Fluctuations in Groundwater Quality
We think of groundwater as moving slowly, and groundwater quality as changing slowly—over decades or even centuries. But in some parts of some aquifers, groundwater quality can fluctuate rapidly, sometimes over just a few hours. Are such changes part of a long-term trend, or just part of a short-term cycle? And what does that mean for suitability for drinking?Predicting Groundwater Quality in Unmonitored Areas
Groundwater provides nearly one-half of the Nation’s drinking water, and sustains the steady flow of streams and rivers and the ecological systems that depend on that flow. Unless we drill a well, how can we know the quality of the groundwater below? Learn about how the USGS is using sophisticated techniques to predict groundwater quality and view national maps of groundwater quality. - Publications
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