TO:Andrew P. Powers, City Manager
FROM:Nader Heydari, Public Works Director
DATE:September 23, 2025
SUBJECT: Triennial Public Health Goal Water Quality Report RECOMMENDATION:
1. Receive Public Health Goal Report and accept public comments on the City of Thousand Oaks’ 2025 Triennial Public Health Goal Report.
2. Find that this action is not a project under the California Environmental Quality Act.
LEVINE ACT ITEM: No
FINANCIAL IMPACT:
No Additional Funding Requested. Staff time to prepare the report is included in the Adopted FY 2025-26 Water Operating Fund Budget.
BACKGROUND:
In 1996, the California Legislature passed Senate Bill (SB) 1307 (Calderone-Sher Safe Drinking Water Act of 1996), which added provisions to the California Health and Safety Code 116470(b). This law requires water utilities with greater than 10,000 service connections to prepare a report every three years regarding applicable state Public Health Goals (PHG) or federal Maximum Contaminant Level Goals (MCLG). Water agencies must analyze the last three years of water quality data and prepare a report that shows which constituents, if any, are above the PHGs or MCLGs. A Public Hearing must then be held to accept comments on the report.
These state and federal goals are not enforceable standards, and water agencies are not required to meet these goals. Most of the PHGs and MCLGs are set at zero or near-zero concentrations and only consider health when developed, without taking into account the cost of treatment, the feasibility of treatment, or the
Triennial Public Health Goal Water Quality Report
September 23, 2025
1 3
8 2
cost of purchasing water for consumers. The enforceable standards, known as Maximum Contaminate Levels (MCL) are also set by the United States Environmental Protection Agency (EPA) and the State Water Resources Control Board (SWRCB) to provide safe drinking water to consumers. When MCLs are developed, they take into account drinking tap water safely over a lifetime, the cost and feasibility of treatment, and the affordability of water for consumers. If water providers fail to meet the MCLs, they must notify the public and take steps to ensure the water complies with the MCLs.
Staff prepared the 2025 Triennial Public Health Goal Report (Attachment #1). Staff also scheduled the Public Hearing to occur on September 23, 2025, and prepared the Notice of Public Hearing that was published in the Ventura County Star newspaper on September 9, 2025. The requirement to prepare PHG reports is unique to California. This report is required in addition to the extensive monthly, quarterly, and annual public reporting of water quality information by California water utilities. The City’s initial PHG report was presented to City Council in 1998.
The legislation requires that subsequent reports be prepared and presented every three years. The triennial PHG report provides information in addition to the Annual Water Quality Report provided to City water customers each spring (Attachment #2).
DISCUSSION/ANALYSIS:
The City’s water supply is of high quality and continues to meet all MCLs, which are the enforceable state and federal standards for safe drinking water. Roughly 170 constituents are regularly tested in the City’s water supply, and 95 of them have established PHGs or MCLGs. During the PHG report testing period of 2022 to 2024, the City’s water supply only had five constituents that were detected above the PHGs or MCLGs. These detections were infrequent, occurred at low levels, and remained much lower than the MCLs. See Attachment #1 for detailed information about these constituents.
The following table lists constituents that were detected above the PHGs or MCLGs, but at levels much lower than the enforceable MCLs. The table also shows that some of the constituents are infrequently above the PHGs or MCLGs and only in a very small fraction of the City’s water supply:
Triennial Public Health Goal Water Quality Report
September 23, 2025
1 3
8 2
See Attachment #1 for discussion about the various water sources the City receives.
The PHG report is presented as an informational document for the public, in compliance with the state requirement to report on constituents that exceeded non- enforceable PHGs. The concentration levels of the constituents noted above were significantly below the MCLs, which are the enforceable levels set by the federal government to ensure that water is safe to consume over a lifetime. No additional actions are required or recommended at this time.
COUNCIL GOAL COMPLIANCE:
Meets the following City Council goals:
B. Provide municipal government leadership which is open and responsive to residents, and is characterized by ethical behavior, stability, promoting public trust, transparency, confidence in the future, and cooperative interaction among civic leaders, residents, business representatives, and staff, while recognizing and respecting legitimate differences of opinion on critical issues facing the City.
F. Provide and enhance essential infrastructure to ensure that the goals and policies of the Thousand Oaks General Plan are carried out and the City retains its role and reputation as a leader in protecting the environment and preserving limited natural resources.
PREPARED BY: Paul Jorgensen, Water Quality Supervisor
Jason Siegert, Environmental Compliance Analyst
Attachments:
Attachment #1 – 2025 Triennial PHG Report
Attachment #2 – 2023 - 2025 Annual Water Quality Reports DPW:1025-40\ev\Council\2025\09232025\Triennial PHG Water Quality staff report.docx Supply Sources MWD Jensen Plant
MWD Weymouth Plant
Calleguas Las Posas Wellfield Calleguas LBWFP
MWD Jensen Plant Calleguas LBWFP
MWD Jensen Plant Calleguas LBWFP68% 24% 6% 2% 99% 1% 98% 2% Arsenic ppb 10 0.004 Range 2.4 ND 2.0 - 5.0 3.0 ND 3.0 ND 2.0 - 4.0Bromate** ppb 10 0.1 Range ND - 15 ND - 7.6 ND ND ND - 14 ND ND - 5.4 NDGross Alpha pCi/L 15 (0) Range ND ND ND - 3.1 ND ND 3.2 ND NDGross Beta pCi/L 50 (0) Range ND - 5.0 4.0 - 7.0 ND 4.2 ND 4.4 ND 5.4 - 5.6Uranium pCi/L 20 0.43 Range ND - 3.0 1.0 - 3.0 1.8 - 2.8 1.4 2.0 - 3.0 1.5 2.0 - 3.0 1.4 - 1.5**The Bromate compliance standard is based on a Running Annual Average, which were below the 10 ppb MCL during the reporting years. Abbreviations:MCL = Maximum Contaminant Level pCi/L = picoCuries per literND = Non-Detect ppb = parts per billion Parameter Units MCL PHG (MCLG)
2022 City of Thousand Oaks Supply
Percent of Supply
Range
2023 2024