Who is responsible for the exterior wall on the Zero lot line property?

In a zero lot line property, the responsibility for the exterior wall typically falls on the property owner whose lot the wall is built on. However, if the wall serves as a boundary between two properties, both owners may share responsibility for its maintenance and repair, often outlined in a mutual agreement or local regulations. It's essential for property owners to consult local laws and any relevant homeowner association rules to clarify their obligations regarding shared walls.