Cal. Public Resources Code § 3184

(a) Within 72 hours of being notified of a reportable leak, pursuant to Section 3183, the supervisor shall determine if the reportable leak poses a significant present or potential hazard to public health and safety, property, or to the environment such that a relief well is necessary. If the supervisor makes that determination, the operator shall immediately begin preparation for, and, as soon as practicable at the determination of the supervisor, commence the drilling of, a relief well. (b) Nothing in subdivision (a) shall prevent the supervisor from making a determination after the initial 72-hour period that a reportable leak poses a significant hazard to public health and safety, property, or to the environment and that a relief well is necessary. If the supervisor makes that determination, the operator shall immediately begin preparation for, and, as soon as practicable at the determination of the supervisor, commence the drilling of, a relief well. (c) If the operator is required to drill a relief well under subdivision (a) or (b), the operator’s efforts to drill the relief well shall continue until the reportable leak has been stopped and the cause of the reportable leak has been fully addressed or the supervisor determines that other means of controlling the reportable leak are appropriate.