The California State Water Resources Control Board’s Division of Drinking Water (DDW) regulates local drinking water quality by setting standards through its Drinking Water Program. The program establishes enforceable standards for regulated contaminants called maximum contaminant levels (MCLs). Primary MCLs address health concerns while secondary MCLs address aesthetics such as taste and odor. The Program also establishes health-based advisory levels for certain unregulated contaminants that lack MCLs, including notification levels (NLs) and response levels (RLs). If monitoring shows a contaminant exceeds its NL, the water system must notify the local governing body and are advised to inform their customers about potential health risks. If the RL is surpassed, DDW recommends taking the affected water source out of service or blending/treating the water below the threshold.
In June of 2026, DDW lowered the NL and RL for manganese in drinking water. The new NL is 0.05 mg/L or 50 ppb (based on a running annual average of quarterly samples) and the new RL is 0.20 mg/L or 200 ppb (based on a single confirmed detection). The revision responds to research on neurotoxic risk to formula-fed infants, who absorb and retain more manganese than adults.
Manganese is frequently encountered in groundwater supplies in the North Coast region. Because the new NL now sits at the same value as the existing secondary MCL for manganese, some water systems that were previously only dealing with aesthetic complaints may now also face NL-triggered notification obligations. Operators will want to keep tabs on manganese levels and plan to respond if testing yields an NL or RL exceedance.
In October 2025, DDW issued new and revised NLs and RLs for perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS), perfluorohexane sulfonic acid (PFHxS), and perfluorohexanoic acid (PFHxA), collectively referred to as PFAS. These new standards respond to the Federal EPA’s adoption of new MCLs for PFAS in April 2024. While the 2024 Federal rule set deadlines for monitoring in 2027 and treatment compliance in 2029, these requirements are now in flux. Separate rules proposed in May of 2026 would either extend the compliance deadline to 2031 or would partially rescind the regulatory determinations and MCLs. Neither has been finalized as of this writing, so systems should keep planning to comply with the existing 2024 rule until the EPA acts.
California has not yet adopted its own enforceable PFAS MCL. A state rulemaking docket exists (SWRCB-DDW-24-001), but as of this writing its procedural dates remain undetermined. In the meantime, DDW regulates PFAS through NL and RL standards, the most recent effective October 2025. While not an MCL violation, exceedance of the NL triggers consumer notification and disclosure obligations. State law for PFAS RL exceedance mandates that water systems take the source offline, treat it, or issue public notifications within 30 days.
General Order DW-2025-0002-DDW, issued December 12, 2025, requires community and non-transient non-community water systems to conduct initial PFAS monitoring on a system-specific schedule (systems are assigned sampling locations and frequencies in an exhibit that DDW updates periodically, most recently in May 2026). This monitoring is also intended to satisfy the federal rule’s initial monitoring requirement. A separate General Order DW-2022-0001-DDW (amended January 29, 2026) governs systems already under monitoring and specifies NL and RL noticing and reporting. Operators who have not already received an individualized monitoring notice from DDW should confirm their status directly with the agency (PFAS@waterboards.ca.gov) rather than assume they are excluded.
Finalized in October 2024, the Federal EPA’s Lead and Copper Rule Improvements (LCRI):
Initial Lead Service Line Inventories (LSLIs) were due to DDW by October 16, 2024. Systems that have not submitted an LSLI should do so immediately as late or missing inventories are grounds for Tier 2/3 public notification. Any system that has identified lead, galvanized requiring replacement, or unknown-material service lines must notify affected customers within 30 days of that determination, and annually thereafter.
California is in the process of incorporating the LCRI into its own drinking water regulations (Title 22 CCR) and implementation is currently targeted for November of 2027. Until that adoption is complete, systems are to continue operating under their existing tap sampling plans.
Fortunately, public funding in the forms of grants and loans is available to systems that need to implement compliance upgrades related to these contaminants. All of the following programs are administered by the State of California’s Division of Financial Assistance (DFA).
The Federal Emerging Contaminants in Small or Disadvantaged Communities (EC-SDC) grant program provides grants to public water systems to address eligible emerging contaminants, including PFAS and manganese. In California, the EC-SDC program has brought over $700M for remediating emerging contaminants to DFA’s Drinking Water State Revolving Fund (DWSRF). Disadvantaged communities (DACs) and/or systems serving under 25,000 people can receive up to 100% of eligible project costs with no expectation of repayment, either as a forgivable loan or, for the smallest DAC systems, an outright grant. Non-DAC systems over 25,000 people can still get up to 50% forgiven on projects up to $25 million. Eligible work includes planning, design, and construction for treatment plant upgrades, new source development, and/or consolidation.
A separate set-aside within the DWSRF is earmarked specifically for lead service line work. DACs can again receive up to 100% principal forgiveness; non-DAC systems can receive zero-interest loans, with forgiveness possible for the DAC-eligible portions of a mixed service territory. This funding can cover both finishing a lagging Lead Service Line Inventory and physical replacement work.
Also administered by DFA, the SAFER Fund (Safe and Affordable Funding for Equity and Resilience) targets systems already experiencing or at risk of drinking water standard violations. SAFER fills gaps the capital project grants may not fund, such as operations and maintenance, system consolidation, and, importantly, interim or emergency water supplies while a permanent fix is designed and built. This critical assistance can help small systems that suddenly have to respond to an RL exceedance for manganese or PFAS and need an immediate stopgap while they plan a more permanent capital project.
DFA also offers Technical Assistance (TA) funding to small or disadvantaged water systems to cover the first steps in planning a compliance project, including engineering analysis, compliance audits, and technical/managerial/financial (TMF) assessments. Through these initial planning tasks, a system can determine if treatment upgrades, consolidation, or new source development is the right course of action to achieve compliance.
At Brelje & Race, we understand that responding to evolving Federal and State regulations can be a real challenge for small water systems. Whether your system is just starting to study compliance upgrades, or is well underway in planning a project, our team of experienced civil engineers are here to help. Our staff bring holistic knowledge of federal and state water regulations, the planning and design of water system improvements, and the diverse resources available to fund system upgrades. We have decades of experience helping Northern California water systems navigate funding, planning, design and construction of compliance projects. Contact us today to learn more about how we can help.
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