Creates the Business Improvement District Law. Provides for the establishment of business improvement districts by a county or municipality by ordinance after petition of a percentage of property owners or business owners, creation of a district plan, notice, and hearings. Provides that a business improvement district may impose district charges on property owners whose real properties are located within the business improvement district or on businesses within a business improvement district. Provides that the county or municipality shall contract with a district management association to administer or implement activities and improvements specified in the district plan. Contains provisions relating to district plans, formation of a district, district boundaries, issuance of bonds, terms and renewal of districts, amendment to district plans, governance of the district, reports of a district management association, dissolution, and legislative purpose. Limits the concurrent exercise of home rule powers. Defines terms. Effective 120 days after becoming law.