California Code, Health and Safety Code - HSC § 44019

(a) Every public agency, including, but not limited to, a publicly owned public utility, owning or operating any motor vehicle that is exempt from annual renewal of registration, and is otherwise subject to this chapter, shall obtain for the vehicle a certificate of compliance with the same frequency as is required for vehicles subject to renewal of registration.  The cost limitations specified in Section 44017 do not apply to any vehicle owned or operated by a public agency.

(b) Certificates of compliance required by subdivision (a) shall be issued if the vehicle meets the requirements of Section 44012 using a test analyzer system meeting the requirements of the department.  Any certificate so issued shall be indexed by vehicle license plate number or vehicle identification number and retained by the public agency for not less than three years, and shall be available for inspection by the department.

(c) Every public agency subject to subdivision (a) shall annually report to the department the number of certificates issued, the number of motor vehicles owned, and the schedule under which the motor vehicles were issued certificates of compliance.

(d) The department may accept proof of compliance with this section other than by a certificate of compliance.