72 Pa. Stat. § 5860.305
When any property is owned by joint tenants or tenants in common, and any such tenant has paid his proportionate amount of taxes due thereon, any taxing district may cause to be filed a claim for the unpaid taxes against the estate, title and interest of the owners who have not paid their proportionate share of the taxes. Whenever a claim for taxes shall have been filed against property owned by joint tenants or tenants in common, the bureau shall release the estate, title and interest of any joint tenant or tenant in common from said claim, upon payment by said joint tenant or tenant in common of his proportionate share of the taxes included therein with proportionate costs. When any property is owned by more than one owner, or part owner, and the estate and title of any owner, or part owner, is either exempt from taxation or has not been made subject by law to taxation, the estate or title of such owner or owners as may not be exempt from taxation, or as has been made subject thereto, shall be subject to taxes in the same manner as any other property liable to assessment for taxes, the claim being filed against all the estate, title and interest of the owner or owners subject to the lien.
72 P.S. § 5860.305