53 Pa. Stat. § 881.206
Each member of the system shall be required to contribute to the fund three per cent of that portion of their actual salary or compensation, including fees where paid in part on a fee basis, on which social security benefits are payable, and six per cent of any salary, compensation or fees in excess of the amount on which social security benefits are payable. However, in the event of a contributor who became a member prior to January 1, 1979, the required rate of contribution shall be the lesser of the rate herein provided and the rate applicable to said member upon his entry into the system.
In order to increase his member's annuity, each member shall also have the option to make contributions for his prior service. Such contributions for prior service may be anticipated in whole or in part at the time the municipality joins the system, or payment thereof or such part thereof as is not anticipated may be spread over a period of time by increasing the payroll deduction of the member by at least one-third. When a member elects to contribute on account of all of his unpaid prior service, his rate of contribution shall be calculated as of his age at the time he first entered the service of the municipality: Provided, however, That any municipality may, at the time it elects to join the system, or at any time thereafter, agree with the board to pay into the fund as part of its liability under and in accordance with section 205 hereof, the moneys necessary to provide the member's contributions for prior service, and in such case no contributions for prior service shall be made by the members.
Member's contributions shall be paid into the fund by the municipality through payroll deductions in such manner and at such time as the board may by rule and regulation determine.
When a municipal employe is employed by more than one municipality, he shall be required to make contributions on account of his salary paid by each municipality. In such cases the board shall provide for the consolidation of credits of the contributor and, upon his retirement, for a consolidated retirement allowance.
53 P.S. § 881.206