Dayton, Maine
Dayton, ME Accessory Dwelling Unit (ADU) Rules
City Acceptance Rating: 7/10
Last Updated: 9.13.2024
Image source: Town of Dayton Facebook
What You Need to Know
The ADU Rules in Dayton are rather lengthy and complicated.
Type of Permit Required
ADUs are permitted through the Code Enforcement Officer of Dayton.
ADU Rules
The owner(s) of the lot on which the Principal Structure, a single-family dwelling, is located must reside in the principal structure or the Accessory Dwelling Unit. Neither the accessory dwelling unit nor the single-family dwelling shall be rented as a Short Term Rental for less than three consecutive months during a twelve (12) month period.
Ownership. The Principal Structure and the Accessory Dwelling Unit shall be held in the same ownership.
One of the occupants of the accessory unit shall be an immediate family member to the owner of the property and resident of the single-family dwelling unit. Immediate family as used in this Ordinance is defined as; spouse, parent, 100 grandparent, brother, sister, child, or grandchild related by blood, marriage, or adoption.
The number of occupants of the accessory unit is limited to two.
The living space, habitable area, of an accessory unit shall be a minimum of 190 square feet and shall not exceed the following percentage of living space of the single family dwelling to which the unit is accessory or the following maximum amounts, whichever are applicable:
The living space of the accessory dwelling unit may not exceed:
If the living space of the single family dwelling is:
40% or 750 sq ft, whichever is greater
Under 2,000 sq ft
35% or 750 sq ft, whichever is greater
2,000 sq ft to 3,000 sq ft
30% or 1,050 sq ft, whichever is greater
3,000 sq ft to 5,000 sq ft
20% or 1,500 sq ft, whichever is greater
Over 5,000 sq ft
Accessory dwelling units are exempt from density requirements or lot area requirements related to the area in which the accessory dwelling unit is constructed.
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.
Only one accessory dwelling unit per principal structure shall be permitted on a lot
An accessory dwelling unit may be constructed only:
Within an existing dwelling unit on the lot;
Attached to or sharing a wall with a single-family dwelling unit; or
As a new structure on the lot for the primary purpose of creating an accessory dwelling unit.
Accessory units are permitted on nonconforming lots, but the structures in which they are located (attached or detached), shall meet the lot coverage and setback requirements for the district in which they are located.
Any new structure constructed on the lot to be an accessory dwelling unit must meet the existing dimensional requirements as required by the municipality for an accessory structure.
Proper ingress and egress shall be provided to the accessory unit.
Attached and internal accessory units shall retain and respect the existing streetscape, character of the neighborhood, and preserve the single-family appearance, architectural style, and character of the original dwelling and property. Outside stairways (either open or closed) that service accessory units on upper stories are permitted, provided that they are integrated into and consistent with the architecture of the building. Outside stairways serving upper stories shall not be located on the side of the building that faces the street, except in the case of a building on a corner lot that fronts two or more streets, a stairway may be allowed on one of the sides of the building that faces a street if no reasonable alternative exists.
All municipal and state buildings codes in effect at the time of application must be followed.
An applicant for a permit for an accessory unit may also apply to the Zoning Board of Appeals for a limited reduction of yard size under Article 9 of this Ordinance where such reduction is reasonably necessary to allow construction of the accessory unit.
Should the owner(s) of the principal structure be found in non-compliance with the standards contained in this section, the non-compliance shall be considered a violation of this Ordinance, and the structure shall revert to a single family dwelling or the previous use.
For an accessory dwelling unit located within the same structure as a single family dwelling unit or attached to or sharing a wall with a single-family dwelling unit, dimensional requirements and setback requirements must be the same as the dimensional requirements and setback requirements of the single-family dwelling unit.
In order for an accessory unit to be located in a detached accessory structure, the following requirements must be met:
The detached accessory structure must be located no further than 100 feet from the nearest point of the principal structure;
The detached accessory structure must be designed and constructed in the style of a garage, barn, storage building, carriage house, or similar structure customarily located on the same lot with a single-family residence.
For an accessory dwelling unit permitted in an existing accessory structure, such as a barn or garage, as of July 1, 2023, the required setback requirements of the zoning district apply.
The accessory dwelling unit and the principal structure must be serviced by common utility meters, unless the utility company providing the service refuses to do so. Should a utility company be unwilling to service the accessory dwelling unit with a common meter, the applicant must provide the Code Enforcement Officer with a letter signed by the utility company so stating, with specific reasons for the refusal.
In order for an accessory dwelling unit to be added to an unsewered lot, the lot must comply with the requirements of the state minimum lot size law, 12 M.R.S.A. §§ 4807 – 4807-G for multiple unit housing as well as all the provisions of the Maine State Plumbing Code and the Town of Dayton Plumbing Ordinance. The applicant shall have the burden to establish the lot area, which may include a survey signed and sealed by a Professional Land Surveyor, at the discretion of the Code Enforcement Officer. The septic system on the property in question shall be functioning properly at the time of application for accessory dwelling unit approval.
The owner of an accessory dwelling unit must provide written verification that each unit of the accessory dwelling unit is connected to adequate water and wastewater services prior to certification of the accessory dwelling unit for occupancy or similar type of approval process. Written verification must include the following:
If an accessory dwelling unit is connected to a public, special district or other comparable sewer system, proof of adequate service to support any additional flow created by the unit and proof of payment for the connection to the sewer system.
If an accessory dwelling unit is connected to a septic system, proof of adequate sewage disposal for subsurface wastewater. The septic system must be verified as adequate by a local plumbing inspector pursuant under section 4221 of Title 30-A. Plans for subsurface wastewater disposal must be prepared by a licensed site evaluator in accordance with Subsurface Wastewater Disposal Rules.
If an accessory dwelling unit is connected to a public, special district or other centrally managed water system, proof of adequate service to support any additional flow created by the unit, proof of payment for the connection and the volume and supply of water required for the unit; and
If an accessory dwelling unit is connected to a well, proof of access to potable water. Any test of an existing well or proposed well must indicate that the water supply is potable and acceptable for domestic use.
Nothing contained in this Section 7.18 or elsewhere in this Ordinance shall be construed to:
exempt a subdivider from the requirements for division of a tract or parcel of land in accordance with the Town’s subdivision ordinance; or b) interfere with, abrogate or annul the validity or enforceability of any valid and enforceable easement, covenant, deed restriction or other agreement or instrument between private parties that imposes greater restrictions than those provided in this section, as long as the agreement does not abrogate rights under the United States Constitution or the Constitution of Maine.