Accessory dwelling units purpose and standards
(a) Accessory dwelling unit (ADU).
(1) Purpose. The intent and purpose of this section is to allow the creation of independent and quasi-independent living spaces that provide accommodations for additional family members or other tenants.
Nothing in this section shall infringe upon the right of an individual to add living space to a home in accordance with existing regulations and codes.
(2) Standards. An (ADU) may be permitted, by right, in any residential zoning district with the following limitations:
a. Accessory dwelling units are only allowed on a lot with one single-family or multi- family dwelling as the principal dwelling and must be clearly subordinate to that principal dwelling. The ADU shall be limited to no more than 900 square feet of building area or 60 percent of the floor area of the principal dwelling (whichever is less) for a studio or one-bedroom unit or no more than 1,200 square feet of building area or 60 percent of the floor area of the principal dwelling (whichever is less) for a two-bedroom unit. In the case a of multi-family dwelling, the ADU shall be no more than ⅔ the size of the largest individual unit.
b. Only one ADU may be allowed per lot, either within or attached to the principal dwelling or located in a new or existing accessory structure. Said accessory structure must meet all other dimensional requirements.
c. Units located within or attached to the principal dwelling may be accessible either through the same means of ingress and egress as the principal dwelling or a separate entrance located to the side or the rear.
d. Either the principal dwelling or the ADU must be owner occupied, except that in the following circumstances, both the principal dwelling and the ADU may be renter occupied:
1. On a lot with a total lot area of 20,000 square feet or more for which the primary use is residential.
2. Where the proposed ADU is located within the existing footprint of the principal dwelling or existing accessory attached or detached structure and does not expand the footprint of the structure.
e. At least one off-street parking space will be provided per ADU bedroom in addition to the required parking spaces of the principal dwelling.
f. Accessory dwelling units located within or attached to the principal dwelling will meet all the requirements of article IV, zoning district dimensional regulations, as they pertain to the principal dwelling.
g. Accessory dwelling units located in a new or existing accessory structure will meet all the requirements of article IV, zoning district dimensional regulations, including all applicable requirements for accessory structures in section 30-111, table of dimensional regulations, and section 30-112(3), yard exceptions. Except that, in no case can an ADU be located in the front yard. However, only where an ADU is proposed to be located on the second floor of an accessory structure such as a garage or workshop, the maximum height of the accessory structure may be increased from 15 feet to 25 feet.
h. The ADU will comply with all applicable state and local regulations.
i. Length of occupancy. All ADUs must be made available for long-term occupancy whether for a family member or through a long-term lease (one-year or more) with a tenant. ADUs shall not be offered or rented for tourist or transient use or through a hosting platform, as such terms are defined in G.L. 1956 § 42-63.1-2.
j. For applications for new primary dwelling units or subdivisions, any proposed ADU shall not be counted toward the density of the proposal for purposes of limiting the number of dwelling units allowed in such development proposal.
k. Special use permit. A request for an ADU which does not comply with the above conditions may be allowed by the zoning board of review subject to the issuance of a special use permit that takes into consideration a recommendation by the planning board. However, zoning relief shall not be required for ADU applications proposed within an existing footprint of the primary or accessory structure which is a legal nonconforming structure in order to address the existing dimensional nonconformity. Further, an application for an ADU which is not allowed by right under this section, shall not, by itself, be reviewed as a minor land development or major land development project.
(Ord. of 10-22-97; Ord. of 3-22-2023 (1); Ord. of 2-26-2025(2))