Upcoming Deadline: Hexavalent Chromium Monitoring Compliance by April 1, 2025

California’s new Hexavalent Chromium Maximum Contaminant Level (MCL) of 10 µg/L goes into effect on October 1, 2024. To comply with California Code of Regulations, Title 22, Section 64432, community and nontransient-noncommunity water systems must complete initial monitoring by April 1, 2025, unless they are using previously approved monitoring data, as outlined below.

What You Need to Know

Who Needs to Monitor?

• All community and nontransient-noncommunity water systems.
• Active groundwater and surface water sources must be tested.
• Standby sources must also be sampled.

Monitoring Requirements

• Initial monitoring: One hexavalent chromium sample must be collected from all active sources.
• Samples must be analyzed by a certified laboratory using either analytical method 218.6 or 218.7.
• If a sample exceeds the MCL, the system must begin quarterly monitoring for that source.

Using Previous Monitoring Data

• Water systems that previously sampled groundwater sources for hexavalent chromium before October 1, 2024, may qualify to use these results if:
  • The sample was collected after October 1, 2022.
  • The sample was analyzed using an approved method.
• To request approval, systems must submit a request to the Division of Drinking Water (DDW).
• Deadline recommendation: Submit your request by November 10, 2024, to allow time for review.
• Important: Previously collected surface water source samples cannot be used to satisfy the initial monitoring requirement.

Key Deadlines to Remember

Need Assistance?

For more details, visit the State Water Board FAQ or contact your BSK project manager at (559) 497-2880.

Stay ahead of the deadline and ensure compliance—schedule your hexavalent chromium monitoring today!

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