The California State Lands Commission is implementing an emergency rule that amends Article 4.7 of Chapter 1, Division 3 of Title 2 of the California Code of Regulations. The emergency rule was effective starting on June 16, 2025.
This emergency rule requires vessels with ballast water sourced from waters with a measured salinity of less than 18 parts per thousand (ppt; i.e., 18 grams of salt per kilogram of water) to conduct ballast water exchange prior to discharging at California’s fresh and brackish water. This requirement is in addition to meeting existing California ballast water discharge performance standards (Performance Standards; Title 2, Cal. Code Regs. Section 2293).
The Maine Invasive Species Program provided information about the emergency rule during a webinar on May 25, 2025.
The approved regulation filed with the Secretary of State is available.