Scarborough, ME Accessory Dwelling Unit (ADU) Rules

Last Updated: 7.2.2024

What You Need To Know

ADUs are permitted within, attached, or detached in Scarborough.

ADUs in Scarborough are permitted through the Code Enforcement Officer..

Only one ADU is permitted per lot.
The owner of the ADU must live in either the primary dwelling or the ADU.
Neither the primary dwelling or ADU can be rented for a period of less than 28 days.
Only two individuals may live in the ADU.
The ADU is limited to 190 square feet or:

If the living space of the single family dwelling is:

Up to 2,000 SF- The living space of the accessory unit shall not exceed 40% or 750 SF, whichever is greater.

2,000 SF to 3,000 SF- The living space of the accessory unit shall not exceed 35% or 750 SF, whichever is greater.

3,000 SF to 5,000 SF- The living space of the accessory unit shall not exceed 30% or 1,050 SF, whichever is greater.

5,000 SF or over- The living space of the accessory unit shall not exceed 20% or 1,500 SF, whichever is greater.

ADUs are exempt from density or lot area requirements as it relates to the area in which an ADU is constructed, but must meet dimensional or setback requirements.
ADUs are permitted within, attached or detached.
ADUs are allowed on nonconforming lots, but the ADU or structure in which it is located must meet dimensional requirements.
Ingress and egress must be available to the ADU.
The design of an attached or ADU within a primary dwelling must be designed with the character of the area and preservation of the appearance of a single family home in mind.

For ADUs within or attached to a primary dwelling, single family dwelling setbacks and dimensional requirements must be followed.
ADUs detached from the primary dwelling cannot be built further than 100 feet from the nearest point of the primary dwelling and must be designed in the style of a barn, storage, building, garage, carriage, house, accessory cottage, or similar structure that you would find on the same lot as a single family residence.
ADUs and the corresponding primary dwelling must be serviced by the same utility meters unless the utility company refuses to do so.

If a utility company refuses, the applicant must provide a letter to the code enforcement officer indicating the reason for their refusal.

For lots that are not connected to public sewer, documentation must be provided that the lot meets the state’s minimum requirements as well as Maine’s plumbing code and Scarborough’s.
The owner of the ADU must provide written confirmation that each unit on the property has adequate water and wastewater services prior to certification of occupancy being given. The written confirmation must include the following:

Proof of adequate service if connected to public sewer
If on septic, proof of adequate sewage disposal and verification through local plumbing inspector
If on a well, must provide proof of potable water

Zoning Ordinance Town of Scarborough- Section 5/Page 24