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 Feb 2011 Apr 2011 Aug 2011 Nov 2011 Feb 2012 May 2012 Aug 2012 Nov 2012 Feb 2013 May 2013 Aug 2013
Chromium-6 Minimum 0.065 0.000 0.040 0.032 0.076 0.044 0.020 0.042 0.047 0.044 0.053
Maximum 0.090 0.140 0.064 0.087 0.11 0.091 0.097 0.074 0.080 0.075 0.074
Average 0.073 0.082 0.056 0.057 0.089 0.074 0.057 0.059 0.060 0.053 0.063

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