California Code, Health and Safety Code - HSC § 40125

Any person entitled to participate in promotional examinations for positions in the county classified civil service shall similarly be entitled to participate in promotional examinations for positions in the classified civil service of the county district, pursuant to the county civil service commission rules in effect at the time, and to be certified for such county positions by the county civil service commission, or other body performing the functions thereof, and to be appointed to such county district positions.