Chromium 6 Regulation September 1, 2015

Topics of Discussion Background Chromium Drinking Water Regulations Impacts on Patterson Water Supply Key Components of Compliance Order Purpose of CAP Other Considerations to Note Public Notification Process

Hexavalent Chromium (Chrome 6) Background What is Chromium? Naturally occurring element found in mineral formations. Exists mainly in two forms: Trivalent Chromium (Chrome 3). Hexavalent Chromium (Chrome 6). Chromium is present in Patterson’s water supply. Presence due to groundwater contact with naturally occurring mineral formations. Current level remains unchanged from historical norms. Presence in groundwater does not pose any acute health risks.

Hexavalent Chromium (Chrome 6) Chromium Drinking Water Regulations Total Chromium (Total Chrome) Federal Total Chrome Maximum Contaminant Level (MCL) is 100 parts per billion (ppb). California Total Chrome MCL is 50 ppb (adopted 1977). Total Chrome includes both Chrome 3 and Chrome 6. Chrome 6 California Chrome 6 MCL is 10 ppb. Adopted July 1, 2014. Chrome 6 is a subset of Total Chrome – It does not replace Total Chrome MCL.

Hexavalent Chromium (Chrome 6) Impact on Patterson Water Supply Patterson is and has been in compliance with Total Chrome MCL. Patterson is not in compliance with new Chrome 6 MCL. Patterson system average for Chrome 6 ranges from 15 to 32 ppb. Regulatory Response: State Water Resources Control Board, Division of Drinking Water (DDW) issued Compliance Order (CO) No. 01_10_15_R_001 dated July 29, 2015. Purpose of CO: Requires Patterson to achieve compliance with Chrome 6 MCL in a reasonable timeframe.

Hexavalent Chromium (Chrome 6) Key Components of Compliance Order (CO) Acknowledgement that Patterson will comply with CO (completed). Quarterly monitoring of groundwater sources for Chrome 6 (implemented). Public notification (in progress). Development of Corrective Action Plan (CAP). Will serve as the “Roadmap” for Patterson to reach compliance. CAP due date to DDW: October 9, 2015.

Hexavalent Chromium (Chrome 6) Purpose of Corrective Action Plan (CAP) Delineate the steps to move Patterson into compliance for Chrome 6. Feasibility Study Pilot/Field Testing and Treatment Process Selection Engineering Design Stages (Conceptual to Final) Permitting Funding/Financing Construction/Commission/Acceptance Time requirements to complete each step. Establish estimated timeline to achieve compliance.

Hexavalent Chromium (Chrome 6) Other Considerations to Note Patterson’s water supply has not changed. DDW recognizes compliance with the Chrome 6 MCL poses a burden to Patterson. DDW is willing to work with Patterson on this issue. Willing to consider changes to the CAP as needed and if reasonable.

Public Notification Process Since this is a Tier 2 Violation, the city must provide the initial public notice to persons served within 30 days. Public notifications will be required every quarter, thereafter, as long as we are out of compliance. Since we are a Community Water System, we must use the following methods for notification: If You Are a… You Must Notify Consumers by… …and By One or More of the Following Methods to Reach Persons Not Likely to be Reached by the Previous Method… Community Water System [64463.4(c)(1)] Mail or direct delivery (a) Publication in a local newspaper Posting in conspicuous public places served by the water system or on the Internet (b) Delivery to community organizations Non-Community Water System [64463.4(c)(2)] Posting in conspicuous locations throughout the area served by the water system (b) Publication in a local newspaper or newsletter distributed to customers Email message to employees or students Posting on the Internet or intranet (b) Direct delivery to each customer Tier 2 violation is anytime an agency exceeds a chemical or radiological MCL.

Secondary Notification Requirements Upon receipt of the city’s notification, the following notification must be given within 10 days: SCHOOLS: Must notify school employees, students, and parents (if the students are minors). RESIDENTIAL RENTAL PROPERTY OWNERS OR MANAGERS (including nursing homes and care facilities): Must notify tenants. BUSINESS PROPERTY OWNERS, MANAGERS, OR OPERATORS: Must notify employees of businesses located on the property.

Questions?