8 Pa.C.S. § 1306

(a) Inspection and reassessment.--If in any borough there is any construction of a building or buildings not otherwise exempt as a dwelling after the council has prepared a duplicate of the assessment of borough taxes and the building is not included in the tax duplicate of the borough, the county assessment office shall, upon the request of the council, direct the assessor in the county assessment office to inspect and reassess, subject to the right of appeal and adjustment provided by statute, all taxable property in the borough to which major improvements have been made after the original duplicates were prepared and to give notice of the reassessments within ten days to the authority responsible for assessments, the borough and the property owner. The real property shall then be added to the duplicate and shall be taxable for borough purposes at the reassessed valuation for that proportionate part of the fiscal year of the borough remaining after the real property was improved. Any improvement made during the month shall be computed as having been made on the first of the month.

(b) Copy of additions or revisions.--A certified copy of the additions or revisions to the duplicate shall be furnished by the council to the borough tax collector, together with their warrant for collection of the taxes, and, within ten days, the borough tax collector shall notify the owner of the real property of the taxes due to the borough.