A Chester County judge has ruled the state’s Mansion House Rule — traditionally used in cases where a residential property straddles a municipal line — may be used to assess taxes for a commercial property that sits on two tax parcels.

Court of Common Pleas Judge Mark L. Tunnell accepted the line of reasoning set forth by the county’s chief assessor to recalculate the tax assessment of two parcels of land under the rule, which can be traced back to 1842.