California Code, Health and Safety Code - HSC § 40121

In fixing compensation to be paid to a person subject to the civil service provisions of this article, the county district board shall provide a salary or wage equal to the salary or wage paid to a county employee for the same quality of service.

This section shall be operative only in a county which is operating under a freeholders' charter which requires that, in the fixing of salaries or wages for persons employed by the county subject to the civil service system of the county, the board of supervisors shall provide a salary or wage at least equal to the prevailing salary or wage for the same quality of service rendered by private persons under similar employment in case such prevailing salary or wage can be ascertained.