53 Pa. Stat. § 1921
Whenever any city, borough, or incorporated town, within this Commonwealth shall have, under existing laws, paved, curbed, and guttered, or otherwise improved, its highways, or any of them, or has opened or graded or acquired or condemned property in or along its highways, or any of them, at the expense in whole or in part of the owners of property bounding and abutting thereon, and such owners or any number of them shall have paid the assessments, levied against them by such city, borough, or incorporated town, or by viewers, for such improvement, into the respective treasury,--the said cities, boroughs, or incorporated towns are hereby authorized and empowered to refund to the said owners, or to their heirs or assigns, the amount of the assessment thus paid by them, if it shall have been determined by any proceeding at law or in equity by a court of competent jurisdiction that the owners of property bounding or abutting on said highway or highways were not liable for the payment of such improvement at the time such improvement was ordered by the council of said cities, boroughs, or incorporated towns to be made.
53 P.S. § 1921