53 Pa. Stat. § 56720
The floating indebtedness, orders or indebtedness of any previous year or years, or carried over from any previous year or years, or indebtedness evidenced by any outstanding promissory note or notes, now existing, by townships of the first class, and now due or to become due, may be funded at any time by the issue and sale at not less than par of bonds, obligations, or certificates, bearing interest at a rate not exceeding six per cent per annum: Provided, That no such bonds, obligations, or certificates shall be issued for a longer period than twenty years from the date thereof, and it shall be the duty of the proper corporate authorities of such township to provide for the payment of principle and interest of all such bonds, obligations, or certificates in the manner now provided by law for increasing the indebtedness of such townships.
53 P.S. § 56720