53 Pa. C.S. § 5620
The effectuation of the authorized purposes of authorities created under this chapter shall be for the benefit of the people of this Commonwealth, for the increase of their commerce and prosperity and for the improvement of their health and living conditions. Since authorities will be performing essential governmental functions in effectuating these purposes, authorities shall not be required to pay taxes or assessments upon property acquired or used by them for such purposes. Whenever in excess of 10% of the land area of any political subdivision in a sixth, seventh or eighth class county has been taken for a waterworks, water supply works or water distribution system having a source of water within a political subdivision which is not provided with water service by the authority, in lieu of such taxes or special assessments the authority may agree to make payments in the county to the taxing authorities of any or all of the political subdivisions where any land has been taken. The bonds issued by any authority, their transfer and the income from the bonds, including any profits made on their sale, shall be free from taxation within the Commonwealth.
53 Pa.C.S. § 5620