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MTBE Report for Public Water System Operators

Pursuant to Water Code Section 13272.1, we are posting the attached report to public water system operators within the Central Coast Region.  The report lists detections of MTBE (methyl tertiary‑butyl ether) in groundwater at underground storage tank (UST) sites reported to this Board during the most recent four full calendar quarters (i.e. April 1, 2012 through March 31, 2013), and supplements previous MTBE reports.  The length of our reporting period has increased to more clearly reflect changes mandated by State Water Board Resolution 2009-0042. Specifically Resolution 2009-0042 required Regional Water Boards and LOP agencies to reduce quarterly monitoring requirements to semiannual or less frequent monitoring at all sites unless site-specific needs warrant otherwise. Check the Geotracker Website for case-specific information and the most current data.

This report, which is organized by county, includes the name and address of the site. The column entitled "MTBE Detection" contains the date of the reported detection of MTBE.  The column entitled "MTBE conc. (ppb)" contains the concentration (in parts per billion) of MTBE detected in groundwater on that corresponding date.

Please review the enclosed list and compare the distance between your supply wells and water intakes to the UST sites.  Also, review the attached graph titled “Investigation Priority Class (A, B, or C)” to determine whether any of these sites fall within the area indicated as “A” on this graph.  For example, if you find a UST site 1000 feet from your well and the concentration reported is 1000 ppb (read across bottom of graph) it would fall within Priority Class “A”.  If you have not already done so, please advise the Water Board staff person assigned to your area as indicated on the attached list.

As a final note, considering the threat posed by releases at operating gasoline service stations, we suggest imposing well protection zones.  You must contact local permitting agencies to implement this option.  We update MTBE data as we receive MTBE information.  On an annual basis, we will post the latest reported MTBE detection dates and maximum MTBE concentrations in groundwater.  For more information regarding sites on the report, please telephone the staff person assigned to your area (see the Priority Classes link ). You can request email notification of the annual list update by sending your purveyor name and email address to Shaelyn Thomas at the Central Coast Water Board. Please enter Purveyor Notification on the subject line.