SECTION 1. Section 1A of chapter 40A of the General Laws is hereby amended by inserting after the definition of “As of right” the following 2 definitions:-

“Cottage cluster”, groupings of no fewer than 4 detached housing units per acre with a footprint of less than 900 square feet each and that include a common courtyard.

“Duplexes”, a residential building that contains 2 dwelling units located on a single lot that share a common wall, common floor or common ceiling.

SECTION 2. Section 1A of chapter 40A of the General Laws is hereby amended by inserting after the definition of “MBTA community” the following definition:-

“Middle housing”, cottage clusters, duplexes, quadplexes, townhouses and triplexes.

SECTION 3. Said section 1A of said chapter 40A is hereby further amended by inserting after the definition of “Permit granting authority” the following definition:-

“Quadplexes”, a residential building that contains 4 dwelling units located on a single lot that share common walls, common floors or common ceilings.

SECTION 4. Said section 1A of said chapter 40A is hereby further amended by inserting after the definition of “Special permit granting authority” the following definition:-

“Townhouses”, a dwelling unit constructed in a row of 2 or more attached units, where each dwelling unit is located on an individual lot or parcel and shares at least 1 common wall with an adjacent unit.

SECTION 5. Said section 1A of said chapter 40A is hereby further amended by inserting after the definition of “Transfer of development rights zoning” the following definition:-

“Triplexes” or “Triple deckers”, a residential building that contains 3 dwelling units located on a single lot that share common walls, common floors or common ceilings.

SECTION 6. Section 3 of said chapter 40A is hereby amended by adding the following 2 paragraphs:-

No zoning ordinance or by-law shall prohibit the development of multi-family housing.

No zoning ordinance or by-law shall impose additional approval standards or requirements on government-assisted housing that aren't applied to similar but unassisted housing.

SECTION 7. Said chapter 40A is hereby further amended by inserting after section 3A the following section:-

Section 3B. (a) A municipality with a population more than 2,500 persons, based on the last federal decennial census, shall adopt a zoning ordinance or by-law that provides for the development of an accessory dwelling unit, as of right, on each lot or parcel zoned for residential use as of January 1, 2023 that allows for the development of detached single-family dwellings. Nothing in this subsection shall prohibit a municipality from the development of middle housing in addition to accessory dwelling units.

(b) A municipality with a population of 10,000 or more persons and less than 25,000 persons, based on the last federal decennial census, shall adopt a zoning ordinance or by-law that provides for the

development of a duplex, as of right, on each lot or parcel zoned for residential use as of January 1, 2023 that allows for the development of detached single-family dwellings. Nothing in this subsection shall prohibit a municipality from the development of middle housing in addition to duplexes.

(c) A municipality with a population of 25,000 or more persons, based on last federal decennial census, shall adopt a zoning ordinance or by-law that provides for the construction of middle housing, as of right, in any area zoned for residential use as of January 1, 2023.

(d) A municipality that provides for the construction of middle housing may regulate the siting and design of middle housing required to be permitted under this section; provided, that the regulations do not, individually or cumulatively, discourage the development of all middle housing types permitted in the area through unreasonable costs or delay. Municipalities may regulate middle housing to comply with protective measures adopted pursuant to statewide land use planning goals.

(e) The executive office of housing and livable communities may grant an extension to the requirements of subsections (a) through (d) under this section. The extension may only be applied to specific areas where the municipality has identified water, sewer, storm drainage or transportation services that are either significantly deficient or are expected to be significantly deficient and for which the municipality has established a plan of actions that will remedy the deficiency in those services; provided, that is approved by the executive office. The extension may not extend beyond the date that the municipality intends to correct the deficiency under the plan.

(f) Annually, each municipality in the commonwealth shall submit a report to the executive office of housing and livable communities explaining how the municipality plans to meet its share of needed housing capacity, as determined by its regional planning agency pursuant to section 31 of chapter 40B, and how new housing construction can meet that goal.

(g) Each municipality in the commonwealth shall review local, regional, state and federal assistance to make housing construction affordable and feasible including but not limited to: grants, loans, rental assistance, tax credits, tax abatements, tax increment financing, bonds, mortgage financing, mortgage insurance, assistance pursuant to any government program or any other form of construction assistance.

(h) Annually, a municipality with 10,000 or more persons, based on the last federal decennial census, shall submit a report to the executive office of housing and livable communities with the number of housing units permitted under this section, broken down by type of housing.

(i) Subject to appropriation, each fiscal year the executive office shall receive and expend, in addition to any other grant or appropriation from the commonwealth or the federal government, $2,000,000 for technical assistance for municipalities to administer this section and develop guidance for the construction of middle housing.

SECTION 8. Chapter 40B of the General Laws is hereby amended by adding the following section:-

Section 31. (a) The board of executive directors of the Massachusetts association of regional planning agencies shall develop a housing needs plan to be submitted annually by each regional planning agency to the executive office of housing and livable communities.

(b) The model plan shall direct each regional planning agency to conduct an evaluation of its member cities' and towns' housing needs using economic and demographic data to determine: (i) the housing needs that their region will face, including projected growth over the next 20 years; (ii) how much housing each municipality would need to reasonably contribute to meet that capacity; (iii) how much buildable land their region has, and what new buildable land they could acquire to help meet their needs.

(c) The executive office of housing and livable communities shall promulgate rules and regulations to implement the purposes of this section.

SECTION 9. Notwithstanding any general or special law to the contrary, the board of building regulations and standards, in coordination with executive office of housing and livable communities, shall review all building codes that might hinder the rehabilitation of single-family residential dwellings into middle housing as that term is defined in section 1A of chapter 40A of the General Laws, and to amend the building code to make it easier to convert buildings into middle housing.

The review shall be filed by the board with the clerks of the house of representatives and the senate no later than June 30, 2024.