Cal. Health and Safety Code § 25283

(a) This chapter shall be implemented by the board, by the regional board, and by the local agency, as defined in subdivision (b), pursuant to the regulations adopted by the board. (b) For purposes of this chapter, “local agency” means the following: (1) (A) A local agency means the unified program agency for purposes of implementing the unified program, as specified in paragraph (3) of subdivision (c) of Section 25404, including the requirements of this chapter and the requirements of any underground storage tank ordinance adopted by a city or county. (B) Consistent with paragraph (3) of subdivision (c) of Section 25404, for purposes of this chapter, a unified program agency does not implement those responsibilities assigned to the state board pursuant to Section 25297.1 or the corrective action requirements of Sections 25296.10 to 25296.40, inclusive. (2) Before July 1, 2013, a local agency means a city or county for purposes of implementing the corrective action requirements of all of the following: (A) Sections 25296.10 to 25296.40, inclusive. (B) Sections 25296.09, 25297, 25297.2, and 25298.5. (C) Sections 25299 to 25299.3, inclusive, with regard to implementing those corrective action requirements. (D) Any other provision of this chapter that relates to implementing a corrective action. (3) On and after July 1, 2013, a local agency means a city or county that is certified by the board to implement the local oversight program pursuant to Section 25297.01 for purposes of implementing the corrective action requirements of all of the following: (A) Sections 25296.10 to 25296.40, inclusive. (B) Sections 25296.09, 25297, 25297.2, and 25298.5. (C) Sections 25299 to 25299.3, inclusive, with regard to implementing those corrective action requirements. (D) Any other provision of this chapter that relates to implementing a corrective action.