California Code, Health and Safety Code - HSC § 9565

A true copy of the plans, specifications, and other information submitted or filed upon which a permit is issued, with the approval of the department with which they are filed, stamped or written on the copy, and signed by the officer or officers authorizing the permit, shall be kept upon the premises of the building for which the permit is issued from the commencement of the work until final completion and acceptance, and shall be subject to inspection at all times by proper authorities.