Notwithstanding Section 31587, and in accordance with Section 31453 or 31510.1, the board may determine county or district contributions on the basis of a normal contribution rate which shall be computed as a level percentage of compensation which, when applied to the future compensation of the average new member entering the system, together with the required member contributions, will be sufficient to provide for the payment of all prospective benefits of such member. The portion of liability not provided by the normal contribution rate shall be amortized over a period not to exceed 30 years.
Ca. Gov. Code § 31453.5