On July 1, 2014, the State Water Resources Control Board - Division of Drinking Water (DDW) standard for hexavalent chromium (chromium-6) took effect. California is the 1st state in the nation to establish a regulation specific to chromium-6, demonstrating a proactive response to a public health concern.
The new standard, or maximum contaminant level (MCL), is 10 parts per billion (ppb). To put that in perspective, 1 ppb is 1 drop of water in a full Olympic-size pool.
Where Chromium-6 Is Found
Chromium-6 tends to be predominately found at highest levels in groundwater because of industrial contamination or naturally occurring mineral deposits. Concerns about the health impacts of chromium-6 have been highlighted by contamination levels measured in cities like Hinkley, California, which was the focus of the movie "Erin Brockovich."
Chromium-6 has not been a concern in CCWD's service area, however, CCWD has actively participated in efforts to develop testing to monitor for the presence of chromium-6 in drinking water. Historically, water quality tests looked at total chromium and did not differentiate down to the molecular form.
The most recent tests run on drinking water produced by CCWD in 2013, detected a range of 0.06 to 0.14 ppb in locations within the distribution system, well below the new MCL.