Small lot residential zoning districts. Requires any locality with a population of 50,000 or more to adopt, maintain, and apply to land within its boundaries at least one zoning district classification that permits a single-family dwelling on a lot with a minimum lot area not exceeding 3,000 square feet. The bill provides that such zoning district classifications shall not impose minimum lot widths exceeding 30 feet or setback, lot coverage, or density requirements that would preclude construction of eligible dwellings on conforming lots. The bill's provisions do not apply to areas within a historic district.