Map showing principal aquifers (PAs) and wells that were sampled as part of a Nationwide assessment of the quality of groundwater used for public supply.
How frequently are volatile organic compounds (VOCs) detected in groundwater?
Volatile organic compounds (VOCs), which are widely used in the manufacture of many products including refrigerants, plastics, adhesives, paints, and petroleum products, have been detected in about one-third of the wells sampled by the National Water-Quality Assessment (NAWQA) Program of the USGS.
- Chloroform and other trihalomethanes, the most commonly detected compounds, were found in about 9 percent of the sampled wells.
- Solvents, particularly chlorinated solvents, were found in about 8 percent of sampled wells.
VOCs predominantly occur in urban areas, often in mixtures; specifically, 2 or more compounds were found in about one quarter of the sampled urban wells.
Learn More: Volatile Organic Compounds in the Nation’s Ground Water and Drinking-Water Supply Wells
Related
How important is groundwater?
Groundwater, which is in aquifers below the surface of the Earth, is one of the Nation's most important natural resources. Groundwater is the source of about 37 percent of the water that county and city water departments supply to households and businesses (public supply). It provides drinking water for more than 90 percent of the rural population who do not get their water delivered to them from...
Where can I find detailed sampling methods for surface water and groundwater?
The National Field Manual for the Collection of Water-Quality Data (National Field Manual) provides guidelines and standard procedures for USGS personnel who collect data used to assess the quality of the Nation’s surface water and groundwater resources. The manual is published as separate chapters. Learn more: Techniques of Water-Resources Investigations Reports
If the ground filters water, is groundwater always clean?
Water drawn from a well was once precipitation that fell onto Earth's surface. It seeped into the ground and, over time, occupied the porous space in some subsurface material. Big particles that are in surface streams, such as leaf chunks, will not be seen in groundwater. So, yes, big particles are filtered out by the ground, along with some minerals and chemicals that are too small to see. But...
Where can I get my well water tested?
Some counties offer free well water testing, so check with your county first. If they don't, use this EPA website to find a list of state-certified laboratories in your area that do water testing, or contact your county or state health department or your State Certification Officer for assistance. Prices will vary depending on the laboratory and the test(s), but most people consider the cost to be...
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, but they are not known to cause health problems...
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 are in it, and at what levels. The U.S...
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 be under a bit of pressure. This causes gases (air)...
What can cause our water to have an earthy odor or to smell like rotten eggs?
Naturally-occurring organic compounds are created when plant material decays in lakes and reservoirs. Those organic compounds frequently cause musty, earthy odors, especially toward the end of summer. The odors can be objectionable, but generally are not harmful to health. However, odors can be caused by other constituents as well, so you might want to call your local Health Department and mention...
Where can I find information about bottled water?
Bottled water is regulated by the U.S. Food and Drug Administration and by individual states. For general information about bottled water, sources include the International Bottled Water Association and NSF International. Learn More: Water bottling across the U.S. - interactive map Water Use - Withdrawals for Bottled Water
Principal aquifers and wells assessed in nationwide NAWQA/GAMA groundwater quality study
Map showing principal aquifers (PAs) and wells that were sampled as part of a Nationwide assessment of the quality of groundwater used for public supply.
Sampling for organic contaminants/Stream Health Synthesis in Root River near Franklin, Wisconsin
linkUSGS scientist collecting a baseflow sample to test for organic contaminants (pharmaceuticals, pesticides, and organic waste compounds), with crest stage gage in the foreground at Root River near Franklin, Wisconsin. https://waterdata.usgs.gov/monitoring-location/04087220/
Sampling for organic contaminants/Stream Health Synthesis in Root River near Franklin, Wisconsin
linkUSGS scientist collecting a baseflow sample to test for organic contaminants (pharmaceuticals, pesticides, and organic waste compounds), with crest stage gage in the foreground at Root River near Franklin, Wisconsin. https://waterdata.usgs.gov/monitoring-location/04087220/
A USGS van outfitted for water quality sampling at an Ohio groundwater well
A U.S. Geological System van, outfitted on the inside with supplies for extensive water quality sampling, parked next to a groundwater well in Ohio. This sampling was conducted as part of a larger effort to assess the occurrence and distribution of per- and polyfluoroalkyl substances (PFAS) in the source waters of public water systems across West Virginia.
A U.S. Geological System van, outfitted on the inside with supplies for extensive water quality sampling, parked next to a groundwater well in Ohio. This sampling was conducted as part of a larger effort to assess the occurrence and distribution of per- and polyfluoroalkyl substances (PFAS) in the source waters of public water systems across West Virginia.
USGS scientist collects groundwater samples to determine water quality
USGS scientist, Rick Arnold collects groundwater samples to determine water quality.
USGS scientist, Rick Arnold collects groundwater samples to determine water quality.
305(b) groundwater quality sampling
305(b) groundwater quality sampling
305(b) groundwater quality sampling
Quality of Our Nation's Groundwater
USGS will describe the occurrence of contaminants in groundwater, how natural features and human activities can affect groundwater quality, and how models are being used to predict contaminant concentrations in unmonitored areas and inform water-resource management decisions.
USGS will describe the occurrence of contaminants in groundwater, how natural features and human activities can affect groundwater quality, and how models are being used to predict contaminant concentrations in unmonitored areas and inform water-resource management decisions.
Groundwater sampling - Long Island
USGS staffer collecting groundwater sample on Long Island
USGS staffer collecting groundwater sample on Long Island
Sampling groundwater
USGS Scientist Lisa Carper testing groundwater samples
USGS Scientist Lisa Carper testing groundwater samples
Sampling recharged groundwater quality beneath an agricultural field
USGS scientist sampling recharged groundwater beneath an agricultural field. Photo from USGS circular 1352 "Water quality in the Glacial Aquifer System, Northern United States, 1993-2009".
USGS scientist sampling recharged groundwater beneath an agricultural field. Photo from USGS circular 1352 "Water quality in the Glacial Aquifer System, Northern United States, 1993-2009".
Related
How important is groundwater?
Groundwater, which is in aquifers below the surface of the Earth, is one of the Nation's most important natural resources. Groundwater is the source of about 37 percent of the water that county and city water departments supply to households and businesses (public supply). It provides drinking water for more than 90 percent of the rural population who do not get their water delivered to them from...
Where can I find detailed sampling methods for surface water and groundwater?
The National Field Manual for the Collection of Water-Quality Data (National Field Manual) provides guidelines and standard procedures for USGS personnel who collect data used to assess the quality of the Nation’s surface water and groundwater resources. The manual is published as separate chapters. Learn more: Techniques of Water-Resources Investigations Reports
If the ground filters water, is groundwater always clean?
Water drawn from a well was once precipitation that fell onto Earth's surface. It seeped into the ground and, over time, occupied the porous space in some subsurface material. Big particles that are in surface streams, such as leaf chunks, will not be seen in groundwater. So, yes, big particles are filtered out by the ground, along with some minerals and chemicals that are too small to see. But...
Where can I get my well water tested?
Some counties offer free well water testing, so check with your county first. If they don't, use this EPA website to find a list of state-certified laboratories in your area that do water testing, or contact your county or state health department or your State Certification Officer for assistance. Prices will vary depending on the laboratory and the test(s), but most people consider the cost to be...
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, but they are not known to cause health problems...
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 are in it, and at what levels. The U.S...
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 be under a bit of pressure. This causes gases (air)...
What can cause our water to have an earthy odor or to smell like rotten eggs?
Naturally-occurring organic compounds are created when plant material decays in lakes and reservoirs. Those organic compounds frequently cause musty, earthy odors, especially toward the end of summer. The odors can be objectionable, but generally are not harmful to health. However, odors can be caused by other constituents as well, so you might want to call your local Health Department and mention...
Where can I find information about bottled water?
Bottled water is regulated by the U.S. Food and Drug Administration and by individual states. For general information about bottled water, sources include the International Bottled Water Association and NSF International. Learn More: Water bottling across the U.S. - interactive map Water Use - Withdrawals for Bottled Water
Principal aquifers and wells assessed in nationwide NAWQA/GAMA groundwater quality study
Map showing principal aquifers (PAs) and wells that were sampled as part of a Nationwide assessment of the quality of groundwater used for public supply.
Map showing principal aquifers (PAs) and wells that were sampled as part of a Nationwide assessment of the quality of groundwater used for public supply.
Sampling for organic contaminants/Stream Health Synthesis in Root River near Franklin, Wisconsin
linkUSGS scientist collecting a baseflow sample to test for organic contaminants (pharmaceuticals, pesticides, and organic waste compounds), with crest stage gage in the foreground at Root River near Franklin, Wisconsin. https://waterdata.usgs.gov/monitoring-location/04087220/
Sampling for organic contaminants/Stream Health Synthesis in Root River near Franklin, Wisconsin
linkUSGS scientist collecting a baseflow sample to test for organic contaminants (pharmaceuticals, pesticides, and organic waste compounds), with crest stage gage in the foreground at Root River near Franklin, Wisconsin. https://waterdata.usgs.gov/monitoring-location/04087220/
A USGS van outfitted for water quality sampling at an Ohio groundwater well
A U.S. Geological System van, outfitted on the inside with supplies for extensive water quality sampling, parked next to a groundwater well in Ohio. This sampling was conducted as part of a larger effort to assess the occurrence and distribution of per- and polyfluoroalkyl substances (PFAS) in the source waters of public water systems across West Virginia.
A U.S. Geological System van, outfitted on the inside with supplies for extensive water quality sampling, parked next to a groundwater well in Ohio. This sampling was conducted as part of a larger effort to assess the occurrence and distribution of per- and polyfluoroalkyl substances (PFAS) in the source waters of public water systems across West Virginia.
USGS scientist collects groundwater samples to determine water quality
USGS scientist, Rick Arnold collects groundwater samples to determine water quality.
USGS scientist, Rick Arnold collects groundwater samples to determine water quality.
305(b) groundwater quality sampling
305(b) groundwater quality sampling
305(b) groundwater quality sampling
Quality of Our Nation's Groundwater
USGS will describe the occurrence of contaminants in groundwater, how natural features and human activities can affect groundwater quality, and how models are being used to predict contaminant concentrations in unmonitored areas and inform water-resource management decisions.
USGS will describe the occurrence of contaminants in groundwater, how natural features and human activities can affect groundwater quality, and how models are being used to predict contaminant concentrations in unmonitored areas and inform water-resource management decisions.
Groundwater sampling - Long Island
USGS staffer collecting groundwater sample on Long Island
USGS staffer collecting groundwater sample on Long Island
Sampling groundwater
USGS Scientist Lisa Carper testing groundwater samples
USGS Scientist Lisa Carper testing groundwater samples
Sampling recharged groundwater quality beneath an agricultural field
USGS scientist sampling recharged groundwater beneath an agricultural field. Photo from USGS circular 1352 "Water quality in the Glacial Aquifer System, Northern United States, 1993-2009".
USGS scientist sampling recharged groundwater beneath an agricultural field. Photo from USGS circular 1352 "Water quality in the Glacial Aquifer System, Northern United States, 1993-2009".
Updated Date: March 25, 2025