ADU Town Rules & Regulations
Cape Elizabeth, ME
May 15, 2026
Last Updated
About
Cape Elizabeth, Maine, is a scenic coastal town known for its breathtaking views of the Atlantic Ocean and its historic landmarks, including the iconic Portland Head Light, one of the most photographed lighthouses in the country. Located just south of Portland, Cape Elizabeth offers a mix of serene natural beauty, with rocky coastlines, beaches, and parks like Fort Williams Park, along with a strong sense of community. Its picturesque charm and proximity to city amenities make it a desirable place for both residents and visitors seeking a peaceful yet energetic seaside atmosphere. As of the 2020 census, Cape Elizabeth had a population of 9,535.
ADU Rules
The following requirements shall apply to the creation of an accessory dwelling unit.
(Effective August 13, 2025):
Single family Parity: An accessory dwelling unit shall be allowed on any lot where a single family dwelling is the principal structure, including nonconforming lots where a single family dwelling may be constructed. (Effective August 13, 2025)
Attached/Detached: An accessory dwelling unit may be constructed only:
Within an existing dwelling unit on the lot;
Attached to a single family dwelling unit; or
As a new structure on the lot or conversion of an existing accessory structure for the primary purpose of creating an accessory dwelling unit. An accessory dwelling unit may be constructed or established within an accessory structure subject to accessory structure setbacks. (Effective July 10, 2024)
Density: An accessory dwelling unit shall be exempt from density or lot size requirements that are in addition to the requirements for the single family dwelling on the lot.
Setbacks: For an accessory dwelling unit located within the same structure as a single family dwelling unit or attached to a single family dwelling unit, the setback requirements and dimensional requirements must be the same as the setback requirements and dimensional requirements of the single family dwelling unit. For an accessory dwelling unit permitted in an existing accessory structure or secondary structure, or garage as of July 1, 2023, the required setback requirements of the existing accessory or secondary structure apply. (Effective August 13, 2025)
Parking: An accessory dwelling unit shall not be subject to any additional motor vehicle parking requirements beyond the parking requirements of the single family dwelling unit on the lot where the accessory dwelling unit is located.
Size: An accessory dwelling unit must meet a minimum size of 190 square feet, unless the Technical Building Codes and Standards Board, pursuant to 10 M.R.S.A Sec. 9722, adopts a different minimum standard; if so, that standard applies. The accessory dwelling unit size shall not exceed 1,200 (one thousand two hundred) square feet and must be a smaller size than the primary dwelling unit. A conversion of an accessory structure that exists as of January 1, 2023 to an accessory dwelling unit shall be exempt from the maximum size. Size shall be measured in compliance with the Floor area of a Structure definition. (Effective August 13, 2025)
Short Term Rental Prohibition: No accessory dwelling unit shall be operated as a Short Term Rental, Sec. 19-8-14, Short Term Rental Standards. (Effective July 10, 2024)
Ownership: The primary dwelling unit and the accessory dwelling unit shall be held in the same ownership or owned in compliance with the requirements of the Maine Condominium Act, 33 MRS Chapter 31. (Effective August 13, 2025)