16 Pa. Stat. § 11674
Should a retiree be reemployed as a county employe, the retirement allowance of such person shall immediately cease. Such person shall thereupon be reinstated as a contributor; and, there shall be restored to his credit as accumulated deductions the actuarial value of his member's annuity computed as of the date of his reemployment. Should he refuse to surrender his right to retirement allowance as of the date of his reemployment, it shall be unlawful for the county to reemploy him. For the purposes of this section if a person serves as a juror, master, or arbitrator or is prohibited from being a member of the system by home rule charter, he shall not be deemed reemployed. If a retiree is reemployed on a part-time basis, the retirement allowance shall not cease, but shall be reduced by an amount equal to the amount of compensation received by the employe for service in excess of 1000 hours per year. Such reduction shall, however, not exceed the amount of the retirement allowance. A retiree reemployed on a part-time basis shall not be reinstated as a contributor and shall not receive additional service credit for retirement purposes.
16 P.S. § 11674