16 Pa. Stat. § 3510
The county commissioners shall have the power to create and maintain a separate capital reserve fund for anticipated legal capital expenditures. The money in the fund shall be used from time to time for the construction, purchase or replacement of or addition to county buildings, equipment, machinery, motor vehicles or other capital assets of the county and for no other purpose.
The county commissioners may, annually, appropriate moneys from the general county funds not to exceed five per cent of the current general county fund budget, to be paid into the capital reserve fund, or place in the fund any moneys received from the sale, lease or other disposition of any county property or from any other source unless received or acquired for a particular purpose. The fund shall be controlled, invested, reinvested and administered, and the moneys therein and income from such moneys expended for any of the purposes for which the fund is created in such manner as may be determined by the county commissioners. The money in the fund when invested shall be invested in securities designated by law as legal investments for sinking funds of municipalities.
This clause shall not be construed to limit the powers of the county to the use of moneys in the capital reserve fund in making lawful capital expenditures.
16 P.S. § 3510