Chromium Report

The Environmental Protection Agency (EPA) regulates total chromium in drinking water. The Maximum Contaminant Level (MCL) for total chromium is 100 parts per billion (ppb). Total chromium includes chromium-3 and chromium-6. The Washington Aqueduct is responsible for drinking water treatment and regulatory testing for total chromium. Total chromium levels are reported in the Washington Aqueduct Annual Report. Currently, individual drinking water standards do not exist for chromium-3 or chromium-6 (hexavalent chromium).

In February 2011, DC Water and the Washington Aqueduct began voluntarily testing for chromium-6 on a quarterly schedule. DC Water collects samples from eight sites in the District's distribution system. The Washington Aqueduct collects samples from the source water (Potomac River) and finished treated water. Samples are tested at an EPA-certified laboratory. For more information about chromium, read the Drinking Water Quality FAQs or visit the EPA. The Washington Aqueduct chromium test results are available here.

Chromium Monitoring Results (part per billion)
Sampling Date February 2011 April 2011 August 2011 November 2011 February 2012 May 2012 August 2012 November 2012 February 2013


Chromium-6		 Minimum 0.065 0.000 0.040 0.032 0.076 0.044 0.020 0.042 0.047
Maximum 0.090 0.140 0.064 0.087 0.11 0.091 0.097 0.074 0.080
Average 0.073 0.082 0.056 0.057 0.089 0.074 0.057 0.059 0.060

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