Cal. Health & Safety Code § 25208.7

(a) The regional board shall make at least one inspection per year of all facilities with surface impoundments, and shall regularly review monitoring data, as necessary, to ensure that all surface impoundments comply with this article and that any equipment or programs required pursuant to this article are operating properly.
(b) Except as provided in subdivisions (c) and (d), each regional board shall establish a schedule and a notification system requiring the submission of reports to the regional board on or before January 1, 1988, by every person discharging liquid hazardous wastes or hazardous wastes containing free liquids into a surface impoundment located within the jurisdiction of the regional board. Any person discharging liquid hazardous wastes or hazardous wastes containing free liquids into a surface impoundment who receives this notice from the regional board shall submit a report to the regional board within the time specified in the notice, except that if the person has filed a report with an application for exemption, pursuant to subdivision (c) of Section 25208.5, the regional board shall not require the person to file a report.
(c) The regional board may require that the report specified in Section 25208.8 be filed by a person who has conducted a site assessment pursuant to subdivision (a) of Section 25208.17 only after the regional board makes the determination specified in subdivision (g) of Section 25208.17.
(d) The regional board may exempt a person from submitting a report specified in Section 25208.8 if the person has ceased discharging into the surface impoundment, the person closed the surface impoundment on or before December 31, 1985, with the approval of the regional board and the department, and the board makes both of the following findings:
1. (1) The report is not required to determine the extent to which the hazardous waste constituents have migrated from the surface impoundment.
2. (2) No hazardous waste constituents are present in the vadose zone or the waters of the state beneath the surface impoundment in concentrations which pollute the vadose zone or threaten to pollute or pollute the waters of the state.