Whenever, in any county subject to the provisions of Section 31676.1 the board of supervisors makes any additional appropriations pursuant to Section 31454.5, the governing body of every district, including the board of supervisors where it is the governing body, also shall make an additional appropriation in the amount to which it has agreed, otherwise in the same proportion as the total pay roll deductions from the salaries of all members employed by such district for the latest pay roll period bear to the total pay roll deductions from the salaries of all members employed by the county for the same pay roll period.
Ca. Gov. Code § 31454.6