Which document is crucial for ensuring compliance with local zoning regulations?

The correct answer is a building permit, as it serves as a formal approval from the local government that indicates a proposed construction project or renovation meets zoning regulations and other legal requirements. Obtaining a building permit is crucial because it ensures that the project aligns with land use laws, including setbacks, height restrictions, and density requirements specific to the zoning designation of the property. The building permit process often involves reviews by various departments, including zoning, to verify compliance with local codes.

In contrast, while a planning application may also be important in initial stages for zoning and development review, it does not serve as a definitive approval for construction. A lease agreement relates to the terms between property owners and tenants, rather than compliance with zoning laws. Lastly, a contractor's license focuses on the qualifications of the contractor to perform work but does not directly address zoning compliance. Therefore, the building permit stands out as the essential document for ensuring that all aspects of the planned construction meet local zoning requirements.