The bill amends several sections of Chapter 45-24 of the General Laws, focusing on zoning ordinances to enhance land use and development standards. It clarifies the means by which attached single-family dwelling units may be created, recorded, and regulated as subdivisions of an existing lot under current zoning ordinance law. The bill allows owners of substandard lots of record with more than one principal dwelling to subdivide the lot such that each dwelling is treated as its own lot, without increased specific requirements for maximum building lot coverage or minimum lot size beyond the footprint of the building to be owned in fee simple.

Additionally, the bill expands the circumstances in which an accessory dwelling unit (ADU) may be allowed by right, reducing the minimum lot size requirement from twenty thousand square feet to ten thousand square feet. It specifies that municipalities may establish maximum unit size regulations for ADUs, allowing for a studio or one-bedroom ADU of up to nine hundred square feet or sixty percent of the gross floor area of the principal dwelling, whichever is less, and for two-bedroom or larger ADUs, up to twelve hundred square feet or sixty percent of the gross floor area of the principal dwelling, whichever is less. Notably, no maximum unit size regulation shall apply where the proposed ADU is located within the existing footprint of the principal dwelling or an existing accessory structure.

The bill also clarifies that municipalities can require year-round occupancy restrictions for ADUs offered for rental occupancy, and such restrictions shall not be subject to the thirty-year limitation on restricted covenants. The legislation aims to promote flexible zoning practices and address housing needs in urban areas while maintaining certain regulatory controls. This act would take effect upon passage.