16 Pa. Stat. § 4973
Whenever the county has available, in any special or appropriation funds other than a sinking fund, moneys for which there is no immediate use, and another special or appropriation fund has immediate and advantageous use for moneys which such fund lacks but the procedure for the securing of which has been consummated, the county commissioners shall have power, by resolution, with the approval of the controller of such county, to temporarily transfer moneys from one special or appropriation fund wherein such moneys are not at the time required to a fund where such moneys can be so advantageously used and expended. Moneys so transferred shall be returned to the fund from which borrowed as soon as sufficient moneys are accumulated in the borrowing fund from authorized sources, except in the case of moneys raised by taxation which are transferred from one budget fund to a similar fund which derives its moneys from taxation, in which cases no such transfer shall be required.
16 P.S. § 4973