California Code, Health and Safety Code - HSC § 78950

(b)(1) If the department or regional board, whichever is overseeing a response action, receives a petition signed by at least 50 members of a community affected by the response action at a site, the department or regional board shall assist the petitioners to establish a community advisory group to review the response action at the site.

(2) If the department or regional board, whichever is overseeing a response action, receives a resolution adopted by the legislative body of the jurisdiction within which the response action has been or will be initiated, the department or regional board shall assist the legislative body to establish a community advisory group to review the response action at the site.