DISTRICT OF COLUMBIA
Serves 581,530 people - Test data available: 2008-2009		  
 
 
  This drinking water quality report shows results of tests conducted by the water utility and provided to the Environmental Working Group (EWG) by the water utility. It is part of EWG's national database that includes 47,667 drinking water utilities and 20 million test results. Water utilities nationwide detected more than 300 pollutants between 2004 and 2009. More than half of these chemicals are unregulated, legal in any amount. Despite this widespread contamination, the federal government invests few resources to protecting rivers, reservoirs, and groundwater from pollution in the first place. The information below summarizes test results for this utility and lists potential health concerns.

The Washington DC Water and Sewer Authority maintains paper records for their water quality tests. The utility provided electronic records for disinfection byproducts only, which are shown below. Contact the utility for the most recent water quality report.

For more information from your water utility, please see their Consumer Confidence Report.

 
This Drinking Water System
National Average
Exceed Health GuidelinesTests showing chemicals at concentrations above health guidelines established by federal and state health agencies. These guidelines are typically set at a levels that pose no significant health risk.
3 chemicals
4
Health Standard ExceedencesChemicals detected at concentrations above the legal limit, the Maximum Contaminant Level (MCLs) established by the U.S. EPA. Most MCLs are based on annual averages, so exceeding the MCL for one test does not necessarily indicate that the system is out of compliance.
0 chemicals
0.5
Pollutants FoundThe total number of contaminants detected since 2004, according to data provided by the state water agency.
4 chemicals
8
Tests ConductedThe total number of number of water quality tests conducted by water utilities and recorded in data provided by the state water agency.
114 tests
420

 
 
 
  Contaminants Exceeding Health Guidelines


Contaminant Average/
Maximum
Result		 Health Limit
Exceeded		 Legal Limit
Exceeded

Testing History

-Tested      -Detected      -Over Health Guidelines      -Over Legal Limit*
Total haloacetic acids (HAAs) 24.76 ppb
35.05 ppb		 Yes
0.7 ppb		 No
60 ppb
Total trihalomethanes (TTHMs) 36.42 ppb
55.85 ppb		 Yes
9.8 ppb		 No
80 ppb
Arsenic (total) 0.34 ppb
0.34 ppb		 Yes
MCLGA non-enforceable health goal that is set at a level at which no known or anticipated adverse effect on the health of persons occurs and which allows an adequate margin of safety. Source: U.S. Environmental Protection Agency.: 0 ppb		 No
10 ppb
NOTE: Each dot in the above graph represents one month.
* Water utilities are noted as exceeding the legal limit if any test is above the maximum contaminant level (MCL). Most MCLs are based on annual averages so exceeding the MCL for one test does not necessarily indicate that the system is out of compliance.

 
 
 
  Other Detected Contaminants

Contaminant Average/
Maximum
Result		 Health Limit
Exceeded		 Legal Limit
Exceeded

Testing History

-Tested &nbsp &nbsp &nbsp-Detected &nbsp &nbsp &nbsp-Over Health Guidelines &nbsp &nbsp &nbsp-Over Legal Limit*
Nitrate 1.65 ppm
1.65 ppm		 No
10 ppm		 No
10 ppm
NOTE: Each dot in the above graph represents one month.
* Water utilities are noted as exceeding the legal limit if any test is above the maximum contaminant level (MCL). Most MCLs are based on annual averages so exceeding the MCL for one test does not necessarily indicate that the system is out of compliance.

 
 
 
  Pollution Summary

4 Total Contaminants Detected (2008 - 2009)

Nitrate, Arsenic (total), Total haloacetic acids (HAAs), Total trihalomethanes (TTHMs)
2 Agricultural Pollutants
(pesticides, fertilizer, factory farms)

Nitrate, Arsenic (total)
2 Sprawl and Urban Pollutants
(road runoff, lawn pesticides, human waste)

Nitrate, Arsenic (total)
2 Industrial Pollutants

Nitrate, Arsenic (total)
2 Water Treatment and Distribution Byproducts
(pipes and fixtures, treatment chemicals and byproducts)

Total haloacetic acids (HAAs), Total trihalomethanes (TTHMs)
2 Naturally Occurring
(naturally present but increased for lands denuded by sprawl, agriculture, or industrial development)

Nitrate, Arsenic (total)
 
 
 
  EPA Violation Summary


Violation Category Number of Violations
MCL and Treatment 2
Reporting 1
Monitoring 1


Information on violations is drawn directly from EPA's national violations database in the Agency's Safe Drinking Water Information System. Analyses by others have raised questions about the quality of the information in EPA's database. For the purposes of this investigation, EWG is not showing below or including in our analyses, those violations for individual water suppliers that occurred on days for which the total number of violations assigned by EPA to that water supplier was greater than 20. This criteria was based on common characteristics of incorrect violations data as identified by water utilities, from a review of EPA's violations data by several hundred utilities prior to the release of EWG's investigation.





Sources : EWG (Environmental Working Group)