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Town of Foster
Town of Foster Zoning Ordinance
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§ 38-282

Development standards for accessory dwelling units

  • (a) ADU type and area requirements. An accessory dwelling unit (ADU) which meets the requirements [of] G.L. § 45-24-31 and G.L. § 45-24-73(a) shall be permitted in the AR, GB, and HC2 zoning districts.

  • (b) ADU permitted by right. Pursuant to G.L. § 45-24-37, one accessory dwelling unit (ADU) shall be allowed by right under the following circumstances:

    • (1) On an owner-occupied property as a reasonable accommodation for family members with disabilities; or

    • (2) On a lot with a total lot area of 20,000 square feet or more for which the primary use is residential; or

    • (3) Where the proposed ADU is located within the existing footprint of the primary structure or existing accessory attached or detached structure and does not expand the footprint of the structure.

  • (c) ADU dimensional regulations.

    • (1) A studio or one-bedroom ADU shall be no larger than 900 square feet, or 60 percent of the floor area of the principal dwelling, whichever is less.

    • (2) A two-bedroom ADU shall be no larger than 1,200 square feet or 60 percent of the floor area of the principal dwelling, whichever is less.

  • (d) ADU application. An application for an accessory dwelling unit which meets the requirements of G.L. §§ 45-24-31 and 45-24-73(a) shall be submitted according to the standards required for a single-family residential building permit. Review shall be conducted by the building official.

  • (e) General ADU provisions.

    • (1) ADUs shall not be restricted based on familial relationships or age unless such restriction is necessary to comply with the terms of the federal subsidy related to affordability.

    • (2) Infrastructure improvements in connection with the ADU including, but not limited to, separate water or sewer service lines or expanded septic system capacity shall not be required unless such improvements and/or modifications are required by an applicable state agency for compliance under state law or regulation, or to comply with building code requirements, or to address capacity or upgrades necessary to accommodate the ADU.

    • (3) Dimensional requirements and development standards on ADUs shall not exceed the requirements for an accessory structure in the same zoning district as the proposed ADU.

    • (4) 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.

    • (5) One off-street parking space shall be required per bedroom of the ADU.

    • (6) ADUs which meet the requirements of G.L. §§ 45-24-31 and 45-24-73(a) shall be permitted as part of applications for new primary dwelling units or subdivisions.

    • (7) For proposed ADUs that are part of a larger development proposal, such ADUs shall not count toward density of the proposal for purposes of limiting the number of dwelling units allowed in such development proposal.

    • (8) The development of ADUs shall not be restricted by any locally adopted ordinance or policy that places a limit or moratorium on the development of residential units in land zoned for residential use.

    • (9) 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. § 42-63.1-2.

  • (f) ADU exceeding permitted standards as of right. An application for an ADU which is not allowed by right under G.L. § 45-24-73(a) shall be prohibited.

If requested, a zoning certificate shall be issued by the building official, pursuant to G.L. § 45-24-54.

(Ord. of 6-23-1994, art. VI, § 11; Ord. of 3-13-2025(10))

Editor's note— An ordinance adopted Mar. 13, 2025, amended the title of § 38-282 to read as herein set out. The former § 38-282 title pertained to development standards for accessory family dwelling units.