40 ILCS 5/18-112.4
An active participant in this System who has at least 6 years of service as a judge and as a participant of this System on August 23, 1989, and who has no creditable service as a participating employee under Article 7 of this Code, may establish service credit in this System: (i) for periods during which the participant held elective office as a member of the board of trustees of a village, and (ii) for any consecutive period not exceeding 5 years during which the participant held appointive office as a member of the zoning board of appeals of the same village in which the participant later held elective office as village trustee, provided such period of appointive office terminated within 12 months prior to the date such period of elective office commenced.
Service credit in this System may be established pursuant to this Section only if the participant did not contribute to the retirement and benefit fund established under Article 7 of this Code for the service sought to be established by the participant in this System, and only if the participant has no equity or rights in that fund because of such service.
Credit for such service may be established in this System by the participant paying to this System an amount equal to (1) contributions at the rate in effect for a judge on the date of becoming a participant in this System multiplied by the salary of the judge on such date for each year of service for which credit is being established, plus (2) the employer's share of the normal cost of benefits under this System, expressed as a percent of payroll, as determined by the System's actuary as of the date of the participant's membership in the System, multiplied by the salary of the judge on such date for each year of service for which credit is being established, plus (3) interest on (1) and (2) above at 6% per annum compounded annually from the date of membership to the date of payment by the participant.
40 ILCS 5/18-112.4