Cal. Gov. Code § 53205.5
Subject to any applicable limitations of Section 53205 the legislative body may authorize payments to the trustees of a fund established to procure insurance pursuant to Insurance Code Sections 10202.8 or 10270.5 (a)(4) and may deduct from the employees' compensation amounts for payment to such trustees; provided, that such payments and such deductions must be the same as payments made by other employers for their employees and payments made by the employees of such other employers, respectively to the trustees of said trust fund. Subject to the trust agreement, the local agency may receive from the trustees a return of payments up to the aggregate expenditures of the local agency. The excess, if any, shall remain in the fund for the benefit of all of the beneficiaries of the trust or their dependents generally.
Ca. Gov. Code § 53205.5