Our change to chloramines in November 2000 has been very effective in our wholesale customers’ distribution systems. This change was made in conjunction with our customers to comply with more stringent federal regulations on levels of disinfection by-products in drinking water. Disinfection is an important step in ensuring that water is safe to drink. Examples of other disinfectants include: chloramines, chlorine dioxide, ozone and ultraviolet light. These disinfectants can react with natural organic matter in the water to form certain unwanted disinfection byproducts. There are two kinds of disinfection: primary disinfection achieves the desired level of microorganism kill or inactivation, while secondary disinfection maintains a disinfectant residual in the finished water that prevents the regrowth of microorganisms.
Our laboratory monitors for the presence of microbiological, organic, radioactive and inorganic contaminants. In addition, we monitor levels for many contaminants which are not regulated but which may affect the aesthetic quality of the drinking water. The link below will provide you with access to our current and historical annual water analysis reports as well as other water quality information. See our Reports page.
Atrazine - Atrazine is a herbicide used in the agriculture industry and it has been found in our waterways. EPA regulates the use of atrazine and the presence of atrazine in drinking water. Under the Safe Drinking Water Act (SDWA), the EPA has determined that no more than 3 parts per billion (ppb) of atrazine (as a running annual average) may be present in drinking water. Under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), the EPA allows Atrazine to be used primarily on corn, sorghum, and sugarcane. It is applied most heavily in the Midwest. Since 1994, our atrazine levels in the water leaving our treatment plants are far below the EPA limits. Our atrazine data can be access at http://washingtonaqueduct.nab.usace.army.mil/water_quality.htm.
The EPA link provided below offers additional information on Atrazine.
http://www.epa.gov/pesticides/reregistration/atrazine/
EPA will evaluate the pesticide’s potential cancer and non-cancer effects on humans. Included in this new evaluation will be the most recent studies on atrazine and its potential association with birth defects, low birth weight, and premature births. Atrazine Science Reevaluation; Potential Health Impacts, October 7, 2009 (EPA-HQ-OPP-2009-0759-0003)
Chloramines - Washington Aqueduct started using chloramine, in addition to chlorine, in November 2000, as a disinfectant to the water it produces. This resulted in a higher quality drinking water.Attached are frequently asked questions detailing the transition to chloramine. Also available is documentation obtained from the Water Research Foundation on the historical perspective of the use of this chemical.
Cryptosporidium - Cryptosporidiumis a parasite commonly found in untreated surface water. Itis very resistant to disinfection, and even in well-operated water treatment plants cannot ensure that treated water is 100% free of Cryptosporidium. Since 1994, we have aggressively tested regularly for Cryptosporidium in our source water. In addition, we are actively involved through our Potomac River Basin Drinking Water Source Protection Partnership to address Cryptosporidium and other emerging contaminants in our watershed. To learn more about the Partnership click here http://www.potomacriver.org/potomacdwspp/.
Fluoride -
We add fluoride to the water to promote dental health. EPA has set an enforceable drinking water standard for fluoride of 4 mg/L. EPA has also set a secondary fluoride standard of 2 mg/L to protect against dental fluorosis. Our fluoride levels are far below EPA standards. The CDC has proclaimed water fluoridation to be one of the top ten greatest public health achievements of the past century. Click here http://www.cdc.gov/fluoridation/fact_sheets/benefits.htm to learn more about community water fluoridation as an effective, safe, and inexpensive way to prevent tooth decay.
Lead in Drinking -
Lead isn’t typically detected in our source or finished water leaving the treatment plants. The most common source of lead in finished drinking water is the customer’s plumbing. We add orthophosphate as a corrosion inhibitor to the finished water to reduce lead leaching from pipes into the drinking water. For more information on the lead levels in the District of Columbia click here http://www.epa.gov/dclead/. For more detail on our Technical Expert Working Group regarding on-going research on lead levels in the District of Columbia click here http://www.epa.gov/dclead/corrosion_research.htm.
Trace Pharmaceuticals -
Pharmaceuticals and personal care products are an emerging concern that the water industry has been researching for years, but one that is not yet well understood. We know the human body often only absorbs small amounts of the various prescriptions and over the counter medicines and dietary supplements that are widely used. Often times these products enter the water supply through agricultural runoff or from human sources. The majority of pharmaceuticals in wastewater enter the water supply when people dispose of medicines in the sink or toilet. We have participated in several studies that tested for pharmaceuticals in our water supply. We will continue to follow the research in pharmaceuticals through our involvement in the Water Research Foundation.
Brief explanation of studies that involved Washington Aqueduct:
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Washington Aqueduct participated in a regional one time-sampling study during June/July 2008. The regional effort was coordinated by the Metropolitan Washington Council of Governments to monitor compounds for select pharmaceuticals, personal care products, and other potential compounds in source and treated water. The results of the study are available on the Metropolitan Washington Council of Governments at: http://www.mwcog.org/environment/water/watersupply/Regional_Results_of_testing_for_19_compounds.pdf
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Washington Aqueduct participated in a USGS National Water – Quality Assessment Program Study during 2003-2005. The USGS study monitored for 277 compounds, including pesticides, solvents, gasoline hydrocarbons, disinfection by-products and personal care products. Data collected at Washington Aqueduct can be downloaded (PODL, Potomac River) and more details on the study can be found at http://pubs.usgs.gov/ds/2007/268.
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Washington Aqueduct participated in the USDA Pesticide Data Program, Finished Drinking Water Monitoring Survey during 2006-2007. The USDA study monitored for 25 pharmaceuticals and personal care products and 173 pesticides and residues. The USDA pesticide data for WA (DC) and information about the study can be downloaded at http://www.ams.usda.gov/science/pdp/Index.htm.
Additional Resources on Pharmaceuticals
U.S. Environmental Protection Agency
For more information on PPCPs, visit the EPA‘s web page at http://www.epa.gov/ppcp/
Water Research Foundation
http://www.waterresearchfoundation.org/research/TopicsAndProjects/projectSnapshot.aspx?pn=3085
American Water Works Association
http://www.drinktap.org/consumerdnn/Home/WaterInformation/WaterQuality/PharmaceuticalsPPCPs/tabid/73/Default.aspx
Drinking Water Contaminant Candidate List and Regulatory Determinations - EPA has drinking water regulations for more than 90 contaminants. The Safe Drinking Water Act (SDWA) requires EPA to list unregulated contaminants which are known or anticipated to occur in public water systems and which may require a national drinking water regulation in the future. .Read More...
Organic Compounds in the Potomac River - An investigation by the National Water-Quality Assessment (NAWQA) Program
of the USGS characterizes the occurrence
of 277 organic compounds in source water
and finished water at the Washington
Aqueduct. Click here to view an abstract of there assessment, prepared November 2008.
Related Links
The memo provides background information on Washington Aqueduct’s implementation of sodium hypochlorite for disinfection and caustic soda for pH control. http://www.epa.gov/dclead/WA_treatment_changes_decision_memo.pdf
Current Drinking Water Regulations: This link provides information on regulations on contaminants EPA regulates in drinking water.
Fact Sheets: The fact sheets provides information on regulated contaminants that may be found in some public or private drinking water supplies.
Health Advisories: This provides information on certain contaminants. Health Advisories are guidance values based on non-cancer health effects for different durations of exposure.
The quality of water being produced at Washington Aqueduct is excellent. Our EPA certified laboratory ensures a quality product that meets or exceeds all United States Environmental Protection Agency (US EPA) drinking water standards. Our laboratory collects and tests thousands of water samples from hundreds of sites which include: raw water intakes, in-house plant samples, reservoirs, and customers’ distribution samples. 
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