California Code, Government Code - GOV § 31564.2

(a) If a district's participation in the retirement system is terminated pursuant to the provisions of Section 31564, the district shall remain liable to the retirement system for the district's share of any unfunded actuarial liability of the system which is attributable to the officers and employees of the district who either have retired or will retire under the retirement system.

(b) Unless otherwise developed by an actuarial source and approved by the board of retirement, the amount of the district's liability shall be the unfunded actuarial liability of the entire system, computed as described below, multiplied by a fraction:

(c) The district's liability shall be paid in accordance with a schedule determined by the retirement board over a period no longer than the period over which the plan's remaining unfunded actuarial liability is being amortized.

(d) The funding of the retirement benefits for the employees of a withdrawing agency is solely the responsibility of the withdrawing agency or the board of supervisors.  Notwithstanding any other provision of law, no contracting agency shall fail or refuse to pay the employer's contribution required by this chapter or to pay the employer's contribution required by this chapter within the applicable time limitations.  In dealing with a withdrawing district, the board of retirement shall take whatever action needed to ensure the actuarial soundness of the retirement system.

(e) The Legislature finds and declares that this section is declaratory of existing law, to the extent this section provides that upon withdrawal from the retirement system, a district shall remain liable for its share of the unfunded actuarial liability of the system.  This section is intended to define the method of calculating the district's share of that unfunded actuarial liability.