Cal. Pub. Resources Code § 3747
Before any work is commenced to abandon any well, the owner or operator shall give written notice to the supervisor or the district deputy of the owner's or operator's intention to abandon the well and the date upon which the work of abandonment will begin.
The notice shall be given at least 10 days before the proposed abandonment, and it shall show the condition of the well and the proposed method of abandonment.
The owner or operator shall furnish the supervisor or the district deputy any additional information that the supervisor or the district deputy may request regarding the condition of the well and the proposed method of abandonment, at any time between the filing of the notice of intention to abandon the well and the completion of abandonment.
Ca. Pub. Res. Code § 3747