California Code, Education Code - EDC § 19104

(a) The board of trustees, common council, or other legislative body of a city or the board of trustees of a library district may, on or before January 1 of any year, notify the county board of supervisors that the city or library district no longer desires to be a part of the county free library system.  The notice shall be accompanied by a statement complying with the requirements of Chapter 8 (commencing with Section 54900) of Part 1 of Division 2 of Title 5 of the Government Code.  The clerk of the board of supervisors shall file the statement with the county assessor and the State Board of Equalization.  Thereafter the city or library district shall cease to participate in the benefits of the county free library system, and the property situated in the city or library district shall not be liable for taxes for county free library purposes.

(b) If the board of trustees, common council, or other legislative body of a city or the board of trustees of a library district intends to withdraw from the county free library system and operate the city's or the district's library or libraries with a private contractor that will employ library staff to achieve cost savings, the requirements of Section 19104.5 shall apply, unless the library or libraries are funded only by the proceeds of a special tax imposed by the city or library district pursuant to Article 3.5 (commencing with Section 50075) of Chapter 1 of Part 1 of Division 1 of Title 5 of the Government Code.