SECTION 1.Section 9 of chapter 40A, as so appearing, is hereby amended by inserting after the second paragraph the following paragraph:-

Zoning ordinances or by-laws shall permit multifamily development by right in one or more zoning districts that together cover not less than 1.5% of the developable land area in a city or town and which, by virtue of its infrastructure, transportation access, existing underutilized facilities, and/or location, are suitable for multifamily residential development.  Zoning ordinances or by-laws shall establish a housing density for by-right multifamily development in such zoning districts of not less than twenty (20) dwelling units per acre.  As used herein, “multifamily housing” means apartment or condominium units in buildings which contain or will contain more than three (3) such units. 

SECTION 2.Section 9 of chapter 40A, as so appearing, is hereby amended by striking out, in the fifth paragraph, the words “cluster developments or”. 

SECTION 3.Section 9 of chapter 40A, as so appearing, is hereby amended by striking out the sixth paragraph and inserting in place thereof the following paragraph:-

Notwithstanding any provision of this section to the contrary, zoning ordinances or by-laws shall provide that cluster developments shall be permitted by right in residential zoning districts at the density permitted in the zoning district in which the property is located upon review and approval by a planning board pursuant to the applicable provisions of sections 81K to 81GG, inclusive, of chapter 41 and in accordance with its rules and regulations governing subdivision control.  Zoning ordinances and by-laws shall not require the submission of a plan showing a standard subdivision complying with the otherwise applicable requirements of the ordinance or by-laws as a condition precedent to the approval of a cluster development plan.

SECTION 4. Section 81Q of chapter 41, as so appearing, is hereby amended by inserting after the second sentence the following sentence:-

Such rules shall not require the submission of a plan showing a standard subdivision complying with the requirements of the local zoning ordinance or by-laws as a condition precedent to the approval of a plan depicting a cluster development pursuant to  section 9 of chapter 40A.

SECTION 5.Section 3 of chapter 40A, as so appearing, is hereby amended by inserting after the tenth paragraph the following paragraph:-

Zoning ordinances and by-laws shall classify “accessory dwelling unit,” as defined herein, as a use permitted by right in all single-family residential zoning districts.  No zoning ordinance or by-law shall unreasonably regulate the location, dimensions, or design of an accessory dwelling unit on a lot.  As used herein, “accessory dwelling unit” is a self-contained housing unit incorporated within a single-family dwelling or detached accessory structure that is clearly subordinate to the single-family dwelling and complies with the use, dimensional, and design requirements of the local zoning ordinance or by-law.