Freeport, Maine
Freeport, ME Accessory Dwelling Unit (ADU) Rules
City Acceptance Rating: 10/10 (10 is most accepting)
Last updated: 8.6..2024
What You Need To Know
Freeport broadened their rules and streamlined their process to allow for ADUs on all lots in which single family or duplex dwellings exist. One ADU is allowed per single family dwelling, and up to two ADUs can be constructed.
Type of ADU Permit Required
ADUs are permitted by right in Freeport and require a building permit.
ADU Rules
Only one ADU permitted is allowed on any lot containing either one or two existing or proposed single family homes or one duplex.
ADUS can be created in one of the following ways:
Using space within an existing single family home or a duplex.
Building an addition onto an existing single family home or duplex.
Use space in an existing accessory structure (not a shed) that is legally existing on or prior to January 1st, 2024.
Detached ADUs built in a structure built on or prior to January 1st, 2024 must adhere to the minimum setback requirements for single family homes and duplexes.
The ADU cannot be greater than 75% of the gross floor area of the largest existing new or single-family dwelling or largest unit in an existing or new Duplex or 1,100 square feet, whichever is lesser.
Any alterations to accommodate an ADU shall maintain the front entrance and residential character of the existing dwelling. Any additional entrance must appear secondary to the main entrance.
No additional parking is required for the ADU.
Water and wastewater requirements must be met.
Resources:
Saco, Maine
Saco, ME Accessory Dwelling Unit (ADU) Rules
City Acceptance Rating: 10/10
Last Updated: 6.10.2024
What You Need To Know
ADUs in Saco are intended to increase affordable housing supply, encourage varied household types, encourage development of existing spaces that maintain the character of the town, and utilities existing utility infrastructure.
Type of ADU Permit Required
ADUs require a building permit in Saco.
ADU Rules
ADUs can be within, attached, or detached and only one ADU is permitted per lot.
ADUS are limited to a maximum of 1,000 square feet and a minimum of 400 square feet.
ADUs square footage is not considered when calculating minimum lot coverage.
ADUs cannot be rented for a period of less than one month.
ADUS must be constructed on permanent foundations.
If public sewer and water services the lot, the ADU and primary residence must be hooked up to public sewer and water.
Detached ADUs
Must have a sprinkler or fire suppression system installed
If constructed attached or within a dwelling, sprinkler or fire suppression systems are only required if they are already installed in the existing dwelling.
Must share the existing driveway of the primary dwelling
Must be designed compatibility to the primary dwelling
Must share the existing driveway.
Resources:
Westbrook, Maine
Westbrook, Maine allows an attached ADUs on property with a maximum of 800 sq ft.
Westbrook, ME Accessory Dwelling Unit (ADU) Rules
City Acceptance Rating: 8/10 (10 is most accepting)
Last updated: 8.6.2024
What You Need To Know
ADUs are allowed in Westbrook where the lot does not have available space to support a second unit. All ADUs must be approved by the Code Enforcement Office. They can be attached, detached, or built as an addition to an existing accessory structure on the property.
Type of ADU Permit Required
Each additional single family dwelling (ADU) is subject to site plan approval by the planning board. In Westbrook, building an ADUs requires a building permit and is approved by the Code Enforcement Office.
ADU Rules
ADUs can be constructed attached to the existing structure, detached, or in an existing accessory structure.
The owner of the principal swelling has to reside either in the ADU or the principal dwelling.
The size of the ADU is limited to a maximum of 800 square feet and minimum of 190 square feet of habitable floor area.
There is only one ADU permitted per lot.
All ADUs must have permanent foundations.
A detached ADU must share the same driveway as the principal dwelling and be constructed to be visually compatible with principal dwelling.
Resources:
https://www.westbrookmaine.com/DocumentCenter/View/4323/Accessory-dwelling-unit_Proposed-Language
Portland, Maine
Portland Maine allows two ADUs on any residential property! A single ADU can be up to 2/3 the size of the primary dwelling unit, or the size of two ADU can be equal to the size of the primary dwelling.
After updating its ADU rules in 2021, Portland has one of the most lenient ADU rules in New England. The rules provide great opportunities to add housing for families or generate rental income in Portland's booming rental market.
Portland, ME Accessory Dwelling Unit (ADU) Rules
City Acceptance Rating: 10/10
Last Updated: 11.14.2024
Image source: Town of Cape Elizabeth
What You Need To Know
ADUs are permitted in Portland on all legal lots, and on qualifying lots, you can build up to two ADUs.
Type of ADU Permit Required
ADUs are permitted by right through the building department.
ADU Rules
Permitted Locations: ADUs allowed on lawfully conforming and nonconforming lots with legal residential uses.
Types of ADUs: Can be new detached structures, building additions, or within existing structures. Nonconformities cannot increase unless specifically permitted.
Number of Units: Up to two ADUs allowed per qualifying property.
Design Considerations: ADUs in nonconforming structures must prioritize adjacent property privacy.
Size Restrictions:
ADU floor area limited to 2/3 of the largest principal unit's gross floor area.
Total detached ADU square footage cannot exceed the principal structure's gross floor area.
Lot Requirements: Exempt from maximum lot coverage and minimum lot area per dwelling unit requirements.
Height Limits: Detached ADUs limited to 18 feet in height or 25 feet if above a garage.
Setbacks: Subject to side and rear setbacks for accessory structures under 250 square feet.
Placement: Detached ADUs prohibited between the principal structure and front lot line.
Resources:
https://static1.squarespace.com/static/5a75f43a692ebeeb1159413d/t/671025bbe5595f4d699c1994/1729111486146/Final+draft+LUC_10_8_24_compressed_reduced.pdf - pages 91-92 of PDF
North Yarmouth, Maine
North Yarmouth, Maine Accessory Dwelling Unit (ADU) Rules
City Acceptance Rating:8/10
last updated 9/24/2020
What you need to know
North Yarmouth has excellent rules for accessory dwelling units with few restrictions.
The town does limit the ADU to 1 bedroom but also has a generous total living area allotment for average sized homes. This means there is likely flexibility in creating an ADU with multiple rooms and only labeling one a bedroom. A bedroom is usually defined by having a clothes closet.
North Yarmouth refers to “Accessory Dwelling Units” as “Accessory Apartments”.
Type of Permit Required:
All types of ADUs only require a building permit and approval by the Code Enforcement Officer.
ADU Rules in North Yarmouth:
The ADU cannot have more than 1 bedroom
The ADU’s living area must not be larger than 40% of the primary home’s homes living area (excluding the basement)
The lot must be in compliance with the minimum lot requirement for its zoning district OR in a subdivision which received approval for smaller lots (open space development)
The primary home or the ADU must be owner-occupied
Only one ADU can be added to a single-family lot
ADUs are exempt from the requirements detailed in section 3.3E Residential Growth Limitation
See the full text here: SECTION 11.1 ACCESSORY APARTMENTS
Yarmouth, Maine
Yarmouth, Maine Accessory Dwelling Unit (ADU) Rules
City Acceptance Rating: 3/10
last updated 9/24/2020
ADU Rules in Yarmouth:
Only one (1) ADU permitted per lot
Maximum of 900 sq ft
ADU must be within required setbacks; ADUs are not eligible for variances to setbacks
Exterior design must be compatible with the existing home on the lot and must be in harmony with and maintain the scale of the neighborhood
Either primary home nor ADU must be primary residence of homeowner and must remain in common ownership
Both the primary home and ADU must be connected to public water and sewer
Detached ADUs are required to have a fire sprinkler system
One (1) parking space is required for the ADU
See the full text here: Site Plan Review Ordinance, Section 702, Article J, Section 13
Scarborough, Maine
Scarborough, ME Accessory Dwelling Unit (ADU) Rules
City Acceptance Rating: 10/10
Last Updated: 7.2.2024
Image source: Green Healthy Maine
What You Need To Know
ADUs are permitted within, attached, or detached in Scarborough.
Type of ADU Permit Required
ADUs in Scarborough are permitted through the Code Enforcement Officer..
ADU Rules
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.
Exterior stairs are not permitted.
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
Resources:
Zoning Ordinance Town of Scarborough- Section 5/Page 24
South Portland, Maine
South Portland, ME Accessory Dwelling Unit (ADU) Rules
City Acceptance Rating: 7/10
Last Updated: 7.2.2024
Image source: MaineBiz
What You Need to Know
ADUs in South Portland can be with an existing dwelling, attached to an existing dwelling, detached from the existing dwelling. There are a number of design considerations that must be taken into account when designing and building an ADU.
Type of Permit Required
ADUs are permitted through the Code Enforcement Officer.
ADU Rules
Size conditions:
For lots under 10,980 square feet, ADUs shall not be greater than 800 square feet or 90% of the principal dwelling, whichever is less.
For lots 10,890 square feet or above, ADUs shall not exceed 10% of the parcel area, 1,200 square feet or 90% of the principal dwelling, whichever is less.
No ADU can be less than 190 square feet of living area.
On properties with two or three dwelling units, the ADU cannot be greater than 90% of the largest legal unit.
The ground floor coverage created from the ADU is limited to 800 square feet.
Ownership
The ADU and the primary dwelling must remain in common ownership.
The owner of the property must reside in either the primary dwelling or the ADU.
Design Considerations:
The ADUs primary entrance cannot be the same as the primary dwelling and must be less visible from the street
There must be a clear relationship between the rooflines of the ADU and the primary dwelling.
The placement of the ADU must maintain the privacy of the residents of the primary dwelling.
The max height of a detached ADU must not exceed 28 feet.
A safe pathway must be created from the ADU to the closest public sidewalk.
No additional parking spaces are required for the addition of an ADU
Uses
ADUs cannot be used as short-term rentals.
Resources:
South Portland Zoning Code- Section 27/Article 15/Page 91
https://www.southportland.org/DocumentCenter/View/1510/CH-27--Zoning-with-New-TOC-format
Falmouth, Maine
Falmouth, Maine Accessory Dwelling Unit (ADU) Rules
City Acceptance Rating: 10/10
last updated 4/13/2020
What you need to know about Falmouth
In 2016 Falmouth, ME revised its Accessory Dwelling Unit (ADU) rules making all types of ADUs allowed by right. This means homeowners can build a 2nd small home on their property without applying for a special permit which saves time, aggravation, and money.
These attractive ADU rules give homeowners the ability to sell their backyard, create space for family, or even build a small home to rent out and generate rental income.
Opportunities in Falmouth, Me:
Sell your un-subdividable backyard
Build a small home to rent out
Create space for family
Type of Permit Required:
ADUs are allowed by right. Homeowners only need to apply for a building permit to build an ADU/small home in their backyard.
Other ADU Rules in Falmouth:
ADUs are allowed by right in all residential zoning districts
The ADUs living area cannot exceed that of the existing house or 850SF, whichever is larger
The ADU and primary house can only have one main entrance. Other entrances must be designed to appear subordinate
Download Falmouth’s full zoning bylaw
Download the Accessory Dwelling Unit rules section
Download lot size and setback requirements.