California Code, Streets and Highways Code - SHC § 909

No agreement entered into by the board of supervisors for the purchase, hire, or rental of any apparatus used in the construction, improvement, or maintenance of highways shall create a charge against the county, unless the agreement complies with all of the following:

All of these writings and copies are public documents.

If a county purchases, hires, or rents any apparatus specified herein pursuant to a local purchasing ordinance, including competitive bidding procedures, it does not have to comply with subdivisions (a), (b), and (c) herein to create a charge against the county.  Compliance with the local purchasing ordinance shall be sufficient to create a charge against the county for said purchase, hire, or rental.