California Code, Public Resources Code - PRC § 5550

(a) The Meyers-Milias-Brown Act, Chapter 10 (commencing with Section 3500) of Division 4 of Title 1 of the Government Code, applies to all districts.

(b) A board of directors may adopt an ordinance establishing an employee relations system that may include, but is not limited to, a civil service system or a merit system.

(c) With the prior permission of the board of supervisors of the principal county, a board of directors may adopt an ordinance that makes the employees of the district subject to the employee relations system of the principal county.  The board of directors may adopt an ordinance that withdraws the employees of the district from the employee relations system of the principal county.  A district in which the employees of the district are subject to the employee relations system of the principal county shall receive employee relations services at cost from the county.