National Water-Quality Assessment (NAWQA) Program

Source Water-Quality Assessment (SWQA) Program


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Quality of Water from Public-Supply Wells in the United States

Transport of Anthropogenic and Natural Contaminants to Supply Wells (TANC)

HBSL (Health-Based Screening Level) Web Site


Toxic Substances Hydrology Program


USGS Organic Geochemistry Research Laboratory




Press Release (December 5, 2008) - Man-Made Chemicals Found in Drinking Water at Low Levels (read)

PODCAST - Source Water-Quality Assessment Coordinator, Greg Delzer, talks about man-made chemicals found in drinking water at low levels (Listen)


(1) To determine the occurrence of about 280 primary unregulated anthropogenic organic compounds in source water used by community water systems.

(2) To understand occurrence patterns in source water and determine if these patterns also occur in finished water prior to distribution.

Featured Publications

Anthropogenic Organic Compounds in Source Water of Nine Community Water Systems that Withdraw from Streams, 200205 - Kingsbury and others, 2008 (Report)

Man-made Organic Compounds in Source Water of Nine Community Water Systems that Withdraw from Streams, 2002–05- Kingsbury and others, 2008 (Fact Sheet)

Organic Compounds in Potomac River Water Used for Public Supply near Washington, D.C., 200305 - Brayton and others, 2008 (Fact Sheet)

Anthropogenic Organic Compounds in Source Water of Selected Community Water Systems that Use Groundwater, 2002–05- Hopple and others, 2009 (Report)

Download the MS PowerPoint slides used to present the findings of the Source Water-Quality Assessments to Congress on December 5, 2008 (Download MS PowerPoint here)

National Water-Quality Assessment Program--Source Water-Quality Assessments - Delzer, 2007 (Fact Sheet)

Concentration data for anthropogenic organic compounds in groundwater, surface water, and finished water of selected community water systems in the United States, 2002-10 - Carter and others, 2010 (Report)

Percent recoveries of anthropogenic organic compounds with and without the addition of ascorbic acid to preserve finished-water samples containing free chlorine, 2004-10 - Valder and others, 2011 (Report)

About These Studies

In 2002, the National Water-Quality Assessment (NAWQA) Program of the U.S. Geological Survey (USGS) implemented Source Water-Quality Assessments (SWQAs) to characterize the quality of selected rivers and aquifers used as a source of supply to community water systems in the United States.  These assessments are intended to complement drinking-water monitoring required by Federal, State, and local programs, which focus primarily on post-treatment compliance monitoring.

Click here to read more details concerning the status of SWQAs.

Role of SWQAs

Collaboration with and complementing work of other Federal, State, and local organizations are important components of SWQAs. Unique characteristics of these assessments, which provide additional information and understanding to other monitoring activities, include:

1. Data on a diverse suite of organic compounds with potential human-health concerns that are not commonly measured in compliance or regulatory programs.

2. The ability to expand the list of compounds monitored to include additional emerging contaminants as analytical methods are approved by USGS.

3. Low-level analytical methods to gain a more complete understanding of contaminant occurrence in source water and finished water.

4. A common sampling approach and laboratory to minimize sample contamination and reduce analytical variability.

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Page Contact Information: Gregory C. Delzer
Maintained by: Joshua F. Valder
Page Last Modified: Thursday, 13-Dec-2012 11:29:29 EST