Drinking Water and Source Water Research
Featured Study: Groundwater quality in the Glacial aquifer system

Are you one of 30 million Americans in the northern U.S. whose drinking-water supply relies on groundwater from the glacial aquifer system? A new USGS study assesses the quality of untreated groundwater from this critical water resource.
Learn MoreFeatured Study: Shale-gas production and groundwater quality
A new USGS study reports that shale-gas production in northern Pennsylvania has not currently caused widespread hydrocarbon contamination in the upland aquifer zone used for domestic supply.
Learn MoreScience Center Objects
Reliable drinking water is vital for the health and safety of all Americans. The USGS works with drinking water facilities and municipal suppliers to monitor and assess the quality of the water used as a source for our nation's drinking water needs.
BACKGROUND
One of the central missions of the USGS is to monitor the natural resources we rely on every day, and one of the most important natural resources monitored is water. As humans, we need water to live, especially clean water. But where does the water we rely on come from? How long can we use it to meet our drinking water needs?
DRINKING WATER IN THE UNITED STATES
Nearly 270 million people rely on public water supply every year1. That means over 85 percent of the United States population depends on municipal water suppliers to provide clean water to their homes and businesses. The source of that water typically is surface water from rivers, lakes, or reservoirs, or groundwater, which is treated before delivery to consumers. The remaining U.S. population relies on private groundwater wells to meet their household needs. The USGS cooperates with drinking water facilities and municipal suppliers to confirm that the source water they use meets its intended purposes, whether those purposes are domestic, commercial, or industrial. The USGS does not regulate or directly monitor water treatment operations, nor does it enforce water-quality standards. But the USGS works with drinking water facilities and municipal suppliers to assess the quality and quantity of the source water they use, whether it comes from a lake, river, reservoir, or groundwater.
RELATED USGS RESEARCH
- Water quality of public supply wells
- Factors affecting the vulnerability of public supply wells to contamination
- Water quality of domestic (private) wells
- Health-based screening levels (HBSLs) for drinking water
- Arsenic and drinking water
- Estimating toxin concentrations from harmful algal blooms in Ohio recreational and source waters
- Harmful algal blooms and drinking water in Oregon
- Groundwater viruses in Minnesota drinking water wells
ADDITIONAL RESOURCES
U.S. Environmental Protection Agency
Examples of research USGS conducts with drinking water and source water.
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Date published: March 1, 2019Status: Active
Public Supply Wells
Are you among the more than 100 million people in the U.S. who relies on a public-supply well for your drinking water? Although the quality of finished drinking water from public water systems is regulated by the EPA, long-term protection and management of the raw groundwater tapped by public-supply wells requires an understanding of the occurrence of contaminants in this invisible, vital...
Attribution: Water Resources, National Water Quality Program
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Date published: March 2, 2019Status: Active
Water Quality in the Nation’s Streams and Rivers – Current Conditions and Long-Term Trends
The Nation's rivers and streams are a priceless resource, but pollution from urban and agricultural areas pose a threat to our water quality. To understand the value of water quality, and to more effectively manage and protect the Nation's water resources, it's critical that we know the current status of water-quality conditions, and how and why those conditions have been changing over time....
Contacts: Lori SpragueAttribution: Water Resources -
Date published: March 1, 2019Status: Active
Domestic (Private) Supply Wells
More than 43 million people—about 15 percent of the U.S. population—rely on domestic (private) wells as their source of drinking water. The quality and safety of water from domestic wells are not regulated by the Federal Safe Drinking Water Act or, in most cases, by state laws. Instead, individual homeowners are responsible for maintaining their domestic well systems and for monitoring water...
Contacts: Leslie A DeSimoneAttribution: Water Resources, National Water Quality Program -
Date published: February 28, 2019Status: Active
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.
Contacts: Bruce LindseyAttribution: Water Resources, National Water Quality Program -
Date published: February 28, 2019Status: Completed
Factors Affecting Vulnerability of Public-Supply Wells to Contamination
More than 100 million people in the United States—about 35 percent of the population—receive their drinking water from public-supply wells. These systems can be vulnerable to contamination from naturally occurring constituents, such as radon, uranium and arsenic, and from commonly used manmade chemicals, such as fertilizers, pesticides, solvents, and gasoline hydrocarbons. Learn about the...
Contacts: Sandra EbertsAttribution: Water Resources, National Water Quality Program -
Date published: January 18, 2019Status: Active
Groundwater viruses in Minnesota drinking water wells
In Minnesota, 74% of the State’s population relies on groundwater to supply their drinking water. Outbreaks of waterborne viral illness have been associated with groundwater, and surveys show that 30 percent of drinking water wells may be contaminated. LIDE is helping the State determine the occurrence of groundwater-borne viruses and the risk of illness in Minnesota groundwater.
Contacts: Joel P Stokdyk, Mark Borchardt -
Date published: February 27, 2018Status: Active
Using models to estimate microcystin concentrations in Ohio recreational and source waters
Cyanobacterial harmful algal blooms (cyanoHABs) and associated toxins, such as microcystin, are a major global water-quality issue. In Lake Erie and inland lakes in Ohio, elevated microcystin concentrations have caused water-resource managers to issue recreational water-quality advisories, and detections of microcystin in source waters have caused drinking-water plant managers to increase...
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Date published: February 2, 2018Status: Active
Harmful Algal Blooms and Drinking Water in Oregon
The occurrence of toxic blue-green algae causes harmful algal blooms in lakes, reservoirs, and rivers and is a growing threat to public health, with human and animal illness and death reported in at least 43 states.
Contacts: Kurt D Carpenter, Stewart RoundsAttribution: Oregon Water Science Center -
Date published: November 4, 2016Status: Active
Biodegradation Of Microcystins In Lake Erie Source Waters And Filters From Drinking-Water Plants
Harmful cyanobacterial “algal” blooms (cyanoHABs) and associated toxins, such as microcystin, are a major global water-quality issue. In Lake Erie, researchers and local health officials have identified the presence of cyanobacterial blooms during the summer and early fall seasons. This is especially pronounced in the Lake Erie Western Basin, where the City of Toledo was forced to issue a do-...
The USGS has a vast library of research on the source water people rely on everyday. Here's a few examples of publications that define the current understanding of the quality of the water supply that makes it into everyday drinking water.
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Year Published: 1997
The U.S. Geological Survey Drinking Water Initiative
Safe drinking-water supplies are critical to maintaining and preserving public health. Although the Nation's drinking water is generally safe, natural and introduced contaminants in water supplies throughout the country have adversely affected human health. This new U.S. Geological Survey (USGS) initiative will provide information on the...
View CitationThe U.S. Geological Survey Drinking Water Initiative; 1997; FS; 047-97; Geological Survey (U.S.)
Assessing the lead solubility potential of untreated groundwater of the United States
In the U.S., about 44 million people rely on self-supplied groundwater for drinking water. Because most self-supplied homeowners do not treat their water to control corrosion, drinking water can be susceptible to lead (Pb) contamination from metal plumbing. To assess the types and locations of susceptible groundwater, a geochemical reaction model...
Jurgens, Bryant; Parkhurst, David L.; Belitz, KennethHormones and pharmaceuticals in groundwater used as a source of drinking water across the United States
This is the first large-scale, systematic assessment of hormone and pharmaceutical occurrence in groundwater used for drinking across the United States. Samples from 1091 sites in Principal Aquifers representing 60% of the volume pumped for drinking-water supply had final data for 21 hormones and 103 pharmaceuticals. At least one compound was...
Bexfield, Laura M.; Toccalino, Patricia; Belitz, Kenneth; Foreman, William T.; Furlong, EdwardQuality of Source Water from Public-Supply Wells in the United States, 1993-2007
More than one-third of the Nation's population receives their drinking water from public water systems that use groundwater as their source. The U.S. Geological Survey (USGS) sampled untreated source water from 932 public-supply wells, hereafter referred to as public wells, as part of multiple groundwater assessments conducted across the Nation...
Toccalino, Patricia L.; Norman, Julia E.; Hitt, Kerie J.Quality of Water from Public-Supply Wells in the United States, 1993-2007Overview of Major Findings
Summary of Major Findings and Implications About 105 million people in the United States-more than one-third of the Nation's population-receive their drinking water from about 140,000 public water systems that use groundwater as their source. Although the quality of finished drinking water (after treatment and before distribution) from these...
Toccalino, Patricia L.; Hopple, Jessica A.Anthropogenic organic compounds in source water of selected community water systems that use groundwater, 2002-05
Source water, defined as groundwater collected from a community water system well prior to water treatment, was sampled from 221 wells during October 2002 to July 2005 and analyzed for 258 anthropogenic organic compounds. Most of these compounds are unregulated in drinking water and include pesticides and pesticide degradates, gasoline...
Hopple, Jessica A.; Delzer, Gregory C.; Kingsbury, James A.Quality of Water from Domestic Wells in Principal Aquifers of the United States, 1991-2004: Overview of Major Findings
More than 43 million people - about 15 percent of the U.S. population - rely on domestic wells as their source of drinking water (Hutson and others, 2004). The quality and safety of water from domestic wells, also known as private wells, are not regulated by the Federal Safe Drinking Water Act or, in most cases, by state laws. Rather, individual...
DeSimone, Leslie A.; Hamilton, Pixie A.; Gilliom, Robert J.Water-quality data for pharmaceuticals and other organic wastewater contaminants in ground water and in untreated drinking water sources in the United States, 2000-01
This report presents water-quality data from two nationwide studies on the occurrence and distribution of organic wastewater contaminants. These data are part of the continuing effort of the U.S. Geological Survey Toxic Substances Hydrology Program to collect baseline information on the environmental occurrence of pharmaceuticals and other organic...
Barnes, Kimberlee K.; Kolpin, Dana W.; Focazio, Michael J.; Furlong, Edward T.; Meyer, Michael T.; Zaugg, Steven D.; Haack, Sheridan K.; Barber, Larry B.; Thurman, E. MichaelTrends in the occurrence of MTBE in drinking water in the Northeast United States
Public water systems in Connecticut, Maine, Maryland, New Hampshire, New Jersey, and Rhode Island sampled treated drinking water from 1993-2006 and analyzed the samples for MTBE. The US Geological Survey examined trends in the occurrence of MTBE in drinking water derived from ground water in these States for two near-decadal time steps; 1993-1999...
Moran, M.J.Vulnerability of shallow groundwater and drinking-water wells to nitrate in the United States
Two nonlinear models were developed at the national scale to (1) predict contamination of shallow ground water (typically < 5 m deep) by nitrate from nonpoint sources and (2) to predict ambient nitrate concentration in deeper supplies used for drinking. The new models have several advantages over previous national-scale approaches. First, they...
Nolan, Bernard T.; Hitt, Kerie J.Workgroup report: Drinking-water nitrate and health - Recent findings and research needs
Human alteration of the nitrogen cycle has resulted in steadily accumulating nitrate in our water resources. The U.S. maximum contaminant level and World Health Organization guidelines for nitrate in drinking water were promulgated to protect infants from developing methemoglobinemia, an acute condition. Some scientists have recently suggested...
Ward, M.H.; deKok, T.M.; Levallois, P.; Brender, J.; Gulis, G.; Nolan, B.T.; VanDerslice, J.VOCs, pesticides, nitrate, and their mixtures in groundwater used for drinking water in the United States
Samples of untreated groundwater from 1255 domestic drinking-water wells and 242 public supply wells were analyzed as part of the National Water-Quality Assessment Program of the U.S. Geological Survey between 1992 and 1999. Wells were sampled to define the regional quality of the groundwater resource and, thus, were distributed geographically...
Squillace, P.J.; Scott, J.C.; Moran, M.J.; Nolan, B.T.; Kolpin, D.W.Explore the tools that show what is happening in the waters around us.
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Date published: March 4, 2019
Groundwater Quality: Decadal Change
Almost one-half of the U.S. population rely on groundwater for their water supply, and demand for groundwater for public supply, irrigation, and agriculture continues to increase. This mapper shows how concentrations of pesticides, nutrients, metals, and organic contaminants in groundwater are changing during decadal periods across the Nation.
Attribution: Water Resources, Upper Midwest Water Science Center -
Date published: September 26, 2016
Water Use Data
Attribution: Virginia and West Virginia Water Science Center
Maps are used to visualize what the data shows. Below are example(s) of maps that highlight drinking water and source water research.
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Date published: May 7, 2014
How much water do we use?
Map viewer used to visualize water use by region and date for U.S. freshwater withdrawals, 1950-present (created by USGS VIZLAB)
Attribution: Water Resources, Oregon Water Science Center
The USGS produces many types of multimedia products. Use the links below to browse our offerings of photograph galleries, podcasts and sound files, videos, aerial photos, and posters related to drinking water and source water.
Drought, Drinking Water and Natural Environments
This short video is one of a series of four total shorts highlighting USGS water science in California's Delta region. The Sacramento-San Joaquin Delta is the hub of the state's water system. Water quality touches on all aspects of life. Teams of U.S. Geological Survey scientists along with their partners monitor water quality and identify sources of pollution and
...Organic Carbon and the World around Us
In this episode, we talk about organic carbon. The benefit of studying carbon extends to many issues, including tracing mercury contamination or investigating disinfection by-products in drinking water treatment. It is amazing what can be discovered by monitoring the volume and flux of carbon through the environment. Learn about the biogeochemistry of carbon from USGS
...What's in Our Water?
In this episode, we are going to investigate more than just the substance "water." We are going to examine what is in our nations' water, how we at the U.S. Geological Survey monitor it, and what tools we have developed to aid those who want to explore more about our planet's most abundant resource. This is the USGS Oregon Science Podcast.
Man-Made Chemicals Found in Drinking Water at Low Levels
Safe drinking water supplies are critical to maintaining and preserving public health. But how healthy is that resource? A recent USGS study found low levels of man-made chemicals in water entering and leaving drinking water treatment plants. USGS lead scientist Greg Delzer explains the findings of this study.
What is E. coli and what should I do if it is in my drinking water?
Listen to hear the answer.
Can you define safe water?
Safe water means water that will not harm you if you come in contact with it. The most common use of this term applies to drinking water, but it could also apply to water for swimming or other uses. To be safe, the water must...
The USGS newsroom distributes media alerts, press releases, and technical memos that highlight new and relevant research.
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Date published: August 8, 2019
Contaminants present in many parts of the Glacial aquifer system
Are you one of 30 million Americans whose drinking-water supply relies on groundwater from the glacial aquifer system? A new USGS study assesses the quality of untreated groundwater from this critical water resource, which underlies parts of 25 northern U.S. states.
Attribution: Water Resources, National Water Quality Program
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Date published: December 7, 2017
Groundwater Quality in the East: The Piedmont and Blue Ridge Crystalline-Rock Aquifers
A regional assessment of untreated groundwater in the Piedmont and Blue Ridge crystalline-rock aquifers, which includes parts of 11 states across the contiguous United States, is now available from the U.S. Geological Survey.
Attribution: Water Resources, National Water Quality Program -
Date published: December 7, 2017
Groundwater Quality in the North: The Glacial Aquifer System
A regional assessment of untreated groundwater in the Glacial aquifer system, which includes parts of 25 states across the northern contiguous United States, is now available from the U.S. Geological Survey.
Attribution: Water Resources, National Water Quality Program -
Date published: December 7, 2017
The Quality of the Nation’s Groundwater: Progress on a National Survey
The U.S. Geological Survey is near the midpoint of a complex undertaking to survey the quality of the nation’s largest drinking-water resource.
Current website: https://www.usgs.gov/news/quality-nation-s-groundwater-progress-a-nation...
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Date published: December 7, 2017
Groundwater Quality in the Southwest: The Rio Grande Aquifer System
A regional assessment of untreated groundwater in the Rio Grande aquifer system, which includes parts of Colorado, New Mexico and Texas, is now available from the U.S. Geological Survey.
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Date published: December 7, 2017
Groundwater Quality in the Midwest: The Cambrian-Ordovician Aquifer System
A regional assessment of untreated groundwater in the Cambrian-Ordovician aquifer system, which includes parts of Minnesota, Wisconsin, Michigan, Iowa, Illinois, Missouri and Indiana, is now available from the U.S. Geological Survey.
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Date published: December 6, 2017
Scientists Home in on Causes of High Radium Levels in Key Midwestern Aquifer
Oxygen levels, dissolved minerals among factors responsible for high concentrations of radium in untreated water from aquifer that underlies six states
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Date published: October 18, 2017
Study Estimates about 2.1 Million People using Wells High in Arsenic
Most Arsenic Presumed to be From Naturally Occurring Sources
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Date published: May 31, 2017
Unconventional Oil and Gas Production Not Currently Affecting Drinking Water Quality
Decades or longer may be needed to fully assess the effects of unconventional oil and gas production on the quality of groundwater used for drinking water in Arkansas, Louisiana, and Texas
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Date published: January 19, 2017
Groundwater Quality in the Southeastern Coastal Plain Aquifer System
A regional assessment of untreated groundwater in the Southeastern Coastal Plain aquifer system is now available from the U.S. Geological Survey.
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Date published: January 19, 2017
Groundwater Quality in Eastern U.S.
A regional assessment of untreated groundwater in the combined Valley and Ridge and Piedmont and Blue Ridge aquifers in the eastern United States is now available from the U.S. Geological Survey.
Below are frequently asked questions associated with the drinking water and source water research.
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Why does my drinking water look cloudy sometimes?
Once in a while you get a glass of water that looks cloudy; maybe milky is a better term. After a few seconds, it miraculously clears up! The cloudiness is due to tiny air bubbles in the water. Like any bubbles, the air rises to the top of the water and goes into the air, clearing up the water. The water in the pipes coming into your house might... -
Where can I find information about my local drinking water supply?
The best way to learn about your local drinking water quality is to read the annual drinking water quality report/consumer confidence report that water suppliers now send out by July 1 of each year. The reports are often sent out with water bills, but they may be sent separately. The reports tell where drinking water comes from, what contaminants... -
What can be causing our drinking water to have a reddish color?
Your water might be affected by iron, which is a commonly-occurring constituent of drinking water. Iron tends to add a rusty, reddish-brown (or sometimes yellow) color to water. If the color is more black than red, your water might contain a combination of iron and manganese. Both of these metals can cause staining of plumbing fixtures or laundry... -
Why are some lakes full of algae and thick plants?
Plants naturally grow in and around lakes, but sometimes lakes and ponds can get an overgrowth of plants, algae, or bacteria. In many cases, humans are responsible. Chemicals that are used on lawns and in agriculture (like nitrogen and potassium) wash into our water systems. Once there, plants and algae have a feast on this “food”. Sometimes...