HomeMy WebLinkAboutAccessory Dwelling Unit OrdinanceTown of Barnstable, MA
§ 240-47.2 § 240-47.2
§ 240-47.2. Accessory dwelling units (ADUs). [Added 7-15-2021 by Order No. 2021-174]
A. Purpose and intent. The intent of permitting accessory dwelling units (ADUs) is to:
(1) Increase the number of dwelling units available for year-round rental in Town while
remaining within our current wastewater capacity limitations;
(2) Adapt single-family residential properties so they are supportive of residents at a variety
of stages in their life cycle;
(3) Encourage greater diversity and support of all populations with particular attention to
young adults and senior citizens; and
(4) Encourage a more economic and efficient use of the Town's housing supply while
maintaining the appearance and character of the Town's single-family neighborhoods;
and
(5) Provide homeowners with a means of obtaining rental income to defray housing costs.
B. Procedural requirements.
(1) An ADU that conforms to the requirements contained herein shall be permitted as an
accessory use to a lawful single-family dwelling use, except that no ADU shall be
permitted on a lot at the same time either an affordable accessory apartment exists on
that lot pursuant to Chapter 9, Article II, §§ 9-12 through 9-16, of the General Ordinances
of the Code of the Town of Barnstable or as a family apartment exists on that lot pursuant
to § 240-47.1.
(2) Prior to issuance of a building permit for an ADU, site plans, floor plans and elevations
shall be submitted showing the proposed interior and exterior changes to existing
buildings or new buildings and improvements on a lot associated with a proposed ADU.
(3) The construction of any accessory dwelling unit must be in conformity with the federal,
state, and local laws and regulations, including all historic, and Old King's Highway
requirements if applicable.
C. Use and dimensional requirements. The Building Commissioner may issue a building permit
authorizing the installation and use of an accessory dwelling unit within a lawful existing or
new single-family dwelling to which the ADU is accessory, or in a new or existing detached
building accessory to and on the same lot as the principal dwelling subject to the following:
(1) No more than one ADU may be created per lot. A Special Permit is required if an applicant
is seeking more than one ADU. This provision is not subject to variance.
(2) If the primary entrance of an ADU is not proposed to be shared with that of the principal
dwelling, such entrance shall be less visible from the street view of the principal dwelling
than the main entrance of the principal dwelling.
(3) An ADU shall be designed so that, to the maximum extent practical, the appearance of
the property on which it is to be located remains that of a single-family residential
property. Any addition or new construction shall be consistent in design with the
principal single-family dwelling, considering the following: architectural details, roof
design, building spacing and orientation, door and window location, and building
Town of Barnstable, MA
§ 240-47.2 § 240-47.2
materials. The ADU 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. Any person aggrieved by the
determination of a Town official with respect to a determination under this subsection
may appeal said determination to the Zoning Board of Appeals.
(4) The ADU shall contain no more than two bedrooms. ADUs, in accordance with the
definition, shall have a maximum gross floor area that is not larger than 1/2 of the
habitable floor area of the principal single-family dwelling unit (exclusive of floor area
that converted to the ADU), or 900 square feet, whichever is smaller. ADUs with more
than two bedrooms and/or a maximum gross floor area greater than 900 square feet may
be permitted by special permit from the Zoning Board of Appeals. Garages, unfinished
attics and basements, common entries, porches and decks shall not be included in the
floor area calculations. [Amended 7-15-2021 by Order No. 2021-175]
(5) Occupancy of the ADU shall not exceed two persons; occupancy limitations shall not
apply to children ages 18 and under. Occupancy of an ADU by more than two persons
over the age of 18 may be permitted by special permit from the Zoning Board of Appeals.
(6) Once an ADU has been added to a single-family dwelling or lot, the accessory dwelling
unit shall not be enlarged beyond the square footage allowed by this section.
(7) All parking for the ADU shall be off street. Prohibits imposing parking requirements in
excess of one parking space per ADU, except that, when an ADU is located not more than
0.5 miles from a commuter rail station, subway station, ferry terminal or bus station, no
parking spaces may be required.
(8) The Board of Health must have documented to the Building Commissioner that sewage
disposal will be satisfactorily provided for in accordance with the provisions of Title 5
and Board of Health regulations, including provisions for an appropriate reserve area on
the site. The principal dwelling unit and accessory dwelling unit shall meet all
wastewater requirements for the combined number of bedrooms/wastewater flow on the
lot. If the property is served by municipal sewer, the Department of Public Works shall
certify adequate capacity is available to serve the additional unit.
(9) The rights and requirements of this section hereby transfer upon the sale of a property
containing an ADU built under the provisions of this section.
(10) An ADU and the principal dwelling to which it is accessory may be rented only in
accordance with the terms of this section.
(11) An ADU shall be used only as a rental, except that the owner of the property may reside
in the ADU while renting the principal dwelling. The rental period for an ADU and for
a principal dwelling shall not be shorter than 12 consecutive months. Either the principal
dwelling or ADU, but not both, may be rented at any given time.
(12) The use of land or structures for an accessory dwelling shall not require owner
occupancy of either the accessory dwelling unit or the principal dwelling
(13) Any commercial use, with the exception of permitted home occupations, shall not be
allowed on a property on which there is an ADU.