California Code, Public Contract Code - PCC § 22030

(a) This article applies only to a public agency whose governing board has by resolution elected to become subject to the uniform construction cost accounting procedures set forth in Article 2 (commencing with Section 22010) and which has notified the Controller of that election. In the event of a conflict with any other provision of law relative to bidding procedures, this article shall apply to any public agency which has adopted a resolution and so notified the Controller.

(b) A county, whether general law or charter, containing a population of less than 500,000 may award individual annual contracts as provided in Section 20128.5.