Cal. Pub. Res. Code § 3125

All work to plug and abandon wells, decommission production facilities, or otherwise remediate well sites that is undertaken, funded, or financed by the division pursuant to Section 3226 or 3255 and performed by outside contractors is public work for which prevailing wages shall be paid for purposes of Chapter 1 (commencing with Section 1720) of Part 7 of Division 2 of the Labor Code.