ZONING BYLAW AMENDMENT / ACCESSORY DWELLING UNITS

To see if the Town will vote to amend Section 2: Definitions, Section 5.4.2.B.(6) Large Additions, Section 5.4.2.B.(7) Garages, Section 5.10.2 Accessory Dwelling Units, and Section 6.1.4 Parking, of the Zoning Bylaw, to revise the requirements for permitting accessory dwelling units as-of-right or by special permit; or take any action related thereto.

Inserted at the request of the Redevelopment Board

VOTE: Favorable Action (5-0)

DISCUSSION
In 2024, Massachusetts passed the Affordable Homes Act, which includes provisions to encourage the production of accessory dwelling units (ADUs) throughout the Commonwealth with the goal of increasing housing options for households of all income levels and at all stages of life. This law establishes that certain ADUs are protected from municipal zoning restrictions that would prohibit, unreasonably restrict, or require a special permit for a single ADU in a single-family residential zoning district through M.G.L. c. 40A, § 3, otherwise known as the Dover Amendment. A Single-Family Residential Zoning District is defined as any zoning district where single-family residential dwellings are a permitted or allowable use, including any zoning district where single-family dwellings are allowed either by-right or by Special Permit.

 
Essentially, under state law, one ADU per lot in a single-family residential zoning district is permitted by-right (without the need for a special permit or variance) subject to the following conditions: 
1. Internal, attached, and detached ADUs are not greater than 900 square feet or ½ of the gross floor area of the principal dwelling, whichever is smaller.
2. No owner-occupancy requirements on either the principal dwelling or ADU. 
3. No unreasonable restrictions on the creation or rental of an ADU not being used as a short-term rental. 
4. No use or occupancy restrictions. 
5. Not more than 1 parking space is required for the ADU, and NO additional parking shall be required for an ADU within 0.5 miles from a commuter rail station, subway station, or bus stop. 

 
Arlington Town Meeting adopted an ADU bylaw in 2021 that currently allows one ADU of up to 900 square feet or ½ of the gross floor area of the principal dwelling, whichever is smaller, per principal dwelling unit in any Residential or Business District as an accessory use to a single-family, two-family, or duplex dwelling, subject to certain conditions, and does not require additional parking spaces. While many provisions of Arlington’s existing ADU section of the bylaw comply with the new state ADU law and regulation, some parts of the bylaw require amendment in order to achieve compliance:
1. The definition for calculating Gross Floor Area has been amended to measure from the interior face, rather than exterior face, of an exterior wall, to be consistent with the State definition. 
2. The purposes in Section 5.10.2.A. are amended to identify ADUs as a method for increasing housing options for smaller households of all income levels, and removes references to familial relationships, local preference, or language that may violate fair housing laws. 
3. Section 5.10.2.B.(1)b) has been amended to clarify that an ADU is not subject to the large additions regulations in Section 5.4.2.B(6).
4. Section 5.10.2.B.(1)d) has been amended to require a special permit for a second ADU on a lot, as required by the state law and regulations.
5. Section 5.10.2.B.(1)e) has been amended to clarify the rules for an ADU proposed for a setback.
6. Section 5.10.2.C.(1) and Section 5.10.2.C.(2) are eliminated because they conflict with the State’s prohibition on owner-occupancy requirements or use restrictions.
7. Section 5.10.2.C.(3) is an administrative correction to correct a reference to an updated Section of the zoning bylaw.
8. Section 8.1.3.D. clarifies that creating an ADU does not impact the nonconforming status of an existing dwelling or accessory building.

 
The ADU bylaw will continue to ban the short-term rental of ADUs.

 
The Board determined that revisions to the ADU bylaw are necessary to maintain compliance with State law and regulations. These revisions were drafted after numerous conversations and discussion among DPCD staff, members of the ARB and Zoning Board of Appeals, the Inspectional Services Director, and Town Counsel.

NOTE: typos in the vote language have been corrected below. The changes are identified in the Corrections to Printed Reports memo in the Reports section of the webpage. 

That the Zoning Bylaw be and hereby is amended as follows:

Amend SECTION 2, Definitions, as follows:

Accessory Dwelling Unit (ADU): A self-contained housing unit, inclusive of sleeping, cooking and sanitary facilities on the same lot as a principal dwelling, which may be detached, attached, or internal to the principal dwelling.

Gross Floor Area: The sum of the horizontal areas of all stories of a building or buildings on a lot, measured from the exterior interior faces of exterior walls, or in the case of a common wall separating two buildings, from the centerline of such common wall as regulated under Section 5.3.22.

Amend Section 5.10.2. Accessory Dwelling Units, as follows:

A.    Purpose. The purpose of this Section 5.10.2 includes is to allow for Accessory Dwelling Units (ADUs) to accomplish the following purposes:

(1)  Increase housing production to address local and regional housing needs across all income levels and at all stages of life.

(2)  Enable property owners to age in place, to downsize, or to earn supplemental income from investing in their properties.

(3)  Provide a more moderately priced housing option to serve smaller households and persons of all income levels and ages.

(4)  Develop small-scale infill housing that provides gentle/hidden density without detracting from the existing character of the affected neighborhoods.

(1)  Promoting the use of accessory dwelling units as a means of providing Arlington property owners with an opportunity to age in place, to create independent living space for elderly, disabled or other family or household members, to downsize or to earn supplemental income from investing in their properties.

(2)  Helping Arlington residents to conserve and grow their own property values.

(3)  Encouraging housing for persons of all income levels and ages.

(4)  Encouraging an orderly expansion of the tax base without detracting from the existing character of the affected neighborhoods.

B.    Requirements

(1)  In any Residential District or Business District, an An accessory dwelling unit is permitted as an accessory use to a principal dwelling in any Residential District, and an accessory dwelling unit is permitted as an accessory use to a principal dwelling for a any single-family dwelling, two-family dwelling, or and duplex dwelling in any Business district, if all of the following conditions are met:

a)    An accessory dwelling unit shall be not be larger in floor area than one-half of the gross floor area of the principal dwelling or 900 square feet, whichever is smaller. For the avoidance of doubt, where an accessory dwelling unit is created by converting a portion of an existing principal dwelling to an accessory dwelling unit, the gross floor area of the resulting accessory dwelling unit shall be measured relative to the gross floor area of the resulting principal dwelling (as affected by or in connection with the conversion).

b)    Any alteration causing an expansion of or addition to a building in connection with an accessory dwelling unit shall not be subject to the provisions of Section 5.4.2.B(6) if and to the extent section 5.4.2.B(6) is otherwise applicable to such alteration or addition.

c)    An accessory dwelling unit shall maintain a separate entrance, either directly from the outside or through an entry hall or corridor shared with the principal dwelling, sufficient to meet the requirements of the State Building Code for safe egress.

d)    No more than oOne (1) accessory dwelling unit on a lot is allowed per principal dwelling unit is permitted as of right, providing the unit complies with the requirements of this Bylaw. A second accessory dwelling unit may be allowed for a second principal dwelling on the same lot if the applicable Special Permit Granting authority, acting pursuant to Section 3.3, grants a Special Permit upon finding that the adverse effects of a second accessory dwelling unit will not outweigh the beneficial impacts to the neighborhood or town, considering the characteristics of the site and of the proposal in relating to the site, providing the second accessory dwelling unit complies with the requirements of this Bylaw.

e)    An accessory dwelling unit may be located in (i) the same building as the principal dwelling unit or as an expansion to such building; (ii) a building that is attached to the principal dwelling unit; or (iii) an accessory building that conforms to the setback requirements of this Bylaw for accessory structures in the district in which it is located., which An accessory building shall not constitute a principal or main building by the incorporation of the accessory dwelling unit. provided that if such If an accessory building is located within 6 feet of a lot line the setback, then such accessory dwelling unit shall be allowed only if the Board of Appeals applicable Special Permit Granting Authority, acting pursuant to Section 3.3, grants a sSpecial pPermit upon its finding that the creation location of such accessory dwelling unit is not substantially more detrimental to the neighborhood or town than the use of such accessory building as a private garage or other allowed use.

f)     An accessory dwelling unit shall not be used as a short-term rental, in accordance with Title V, Article 18, Section 3 of the By-Laws of the Town of Arlington.

g)    An accessory dwelling unit shall be subject to all applicable requirements of the State Building Code and State Fire Code (including any such requirements, if and as applicable, which prohibit openings, including windows, in exterior walls of dwellings located within a certain distance from the property line).

(2)  The creation or addition of an accessory dwelling unit shall not change the zoning classification of the property in question and shall not affect any zoning relief previously obtained for such property. By way of example only (and without limitation), a single-family dwelling having an accessory dwelling unit shall continue to be classified as a single-family dwelling for single-family use under the Zoning Bylaw; a two-family dwelling having an accessory dwelling unit shall continue to be classified as a two-family dwelling for two-family use under the Zoning Bylaw; and a duplex having an accessory dwelling unit shall continue to be classified as a duplex dwelling for duplex use under the Zoning Bylaw.

(3)  No off-street parking spaces are required in connection with the creation or addition of an accessory dwelling unit.

(4)  An accessory dwelling unit shall not be owned separately from the principal dwelling unit with which such accessory dwelling unit is associated.

3. Administration

(1)  Prior to the issuance of a building permit for an accessory dwelling unit, the owner must deliver an affidavit to the building inspector stating that the owner or a family member of the owner will reside in either the principal dwelling unit or the accessory dwelling unit upon completion of the accessory dwelling unit.

(2)  The creation or addition of an accessory dwelling unit to a principal dwelling unit shall not be subject to the foregoing paragraph 5.9.2.C(1) if the principal dwelling unit and accessory dwelling unit are owned by a non-profit or governmental entity and the accessory dwelling unit is restricted as an affordable unit.

(3) In the event of any conflict or inconsistency between the provisions of this Section 5.910.2 or Section 8.1.3.D, on the one hand, and any other provisions of this Bylaw, the provisions of this Section 5.910.2 and Section 8.1.3.D shall govern and control.

Amend Section 8.1.3. Nonconforming Single-Family or Two-Family Dwellings, as follows:

[…]

D.    The creation or addition of an accessory dwelling unit within an existing single-family dwelling, two-family dwelling, or duplex dwelling, or within an existing accessory building on the same lot as any such dwelling, does not increase or affect the nonconforming nature of an existing dwelling or accessory building, and shall not cause such dwelling or accessory building to become non-conforming or result in any additional dimensional requirements with respect to such dwelling or accessory building, provided that such creation or addition of an accessory dwelling unit neither expands the footprint nor the height of said dwelling or accessory building, in each case except (i) for changes necessary to provide for required egress or other modification to meet the State Building Code and State Fire Code, (ii) for any projects allowed under Section 5.3.9, and (iii) to the extent authorized by a special permit issued pursuant to clause (iii) of Section 5.10.2.B(1), fifth bullet.

Redevelopment Board Report

Amendment, Wynelle Evans, Precinct 14

ARB Presentation

Memo – ADU Legislation, Claire Ricker, DPCD