Can I build an ADU in Gorham, Maine?
Yes. Gorham calls ADUs "accessory apartments." One is allowed on any lot where a single-family home is allowed or exists, with Code Enforcement Officer approval. It can be attached or detached, must be 190 to 800 sq ft, and the owner must live on the property.
| Where allowed | All districts that allow single-family homes, or any lot with an existing single-family home [1] |
| Approval | Code Enforcement Officer [1] |
| Owner occupancy | Owner must live in the main house or the apartment [2] |
| Size | 190 to 800 sq ft of living space [3] |
| Occupants | Maximum 2 [2] |
| Number per lot | 1 [6] |
| Parking | No extra spaces required (ADUs exempt) [7] |
| Setbacks | Same as the zoning district; shoreland rules if applicable [5] |
Where you can build one
Section 2-4.C makes an accessory apartment a permitted use in every zoning district that allows single-family homes, and on any lot where a single-family home already exists, subject to Code Enforcement Officer approval [1]. Accessory apartments are also listed by name as permitted uses in the Urban Residential, Suburban Residential and Rural districts. Chapter 1 defines an accessory apartment as a separate dwelling unit added on to, or created within, a lot with a single-family house.
Size, occupancy and number
- The owner must live in either the main house or the apartment, and no more than two people may live in the apartment [2].
- Living space must be between 190 and 800 sq ft [3].
- Only one accessory apartment is allowed per lot [6].
- It doesn't count as an extra dwelling unit for lot-area-per-unit limits, but it must meet the district setbacks and any shoreland zoning rules [5].
Attached or detached
Both are allowed. The utility rules differ: if public sewer is available you must connect, and a detached unit needs its own sewer lateral. Without sewer, an attached unit may share an expanded septic system, but a detached unit needs its own separate septic system [4]. On a private well, you must show the water is potable before a certificate of occupancy is issued. If public water is available, you must connect and give Code Enforcement a Portland Water District ability-to-serve letter before the building permit.
Parking
The off-street parking table requires 2 spaces per single-family home and says accessory dwelling units are exempt [7].
State law
Gorham's owner-occupancy rule is allowed for now, but Maine law bars towns from requiring owner occupancy starting July 1, 2027. The state's minimum ADU size is 160 sq ft, so Gorham's 190 sq ft minimum may conflict with state law. The Chapter 2 file we reviewed is dated July 2025. A reported August 2025 amendment to Section 2-4 may not be included, so check the current rules with Code Enforcement.
See how Gorham compares with 8+ other Maine towns on accessory dwelling units (adus) →
Next steps
- Confirm your lot has, or allows, a single-family home and check your district setbacks.
- Plan the unit at 190-800 sq ft, for no more than 2 occupants, and decide whether you or the tenant will live in the main house.
- Get utility sign-off: a Portland Water District sewer and water plan or ability-to-serve letter, or, on septic, the HHE-220 form the code requires if your system must be expanded.
- Apply to Gorham Code Enforcement (207-222-1605) for accessory apartment approval and a building permit, then get a certificate of occupancy before anyone moves in.
Common questions
- Can I build an ADU in Gorham, Maine?
- Yes. Gorham calls ADUs "accessory apartments." One is allowed on any lot where a single-family home is allowed or exists, with Code Enforcement Officer approval. It can be attached or detached, and the owner must live on the property.
- How big can an accessory apartment be in Gorham, Maine?
- Living space must be between 190 and 800 sq ft, with a maximum of 2 occupants. The page notes that the state's minimum ADU size is 160 sq ft, so Gorham's 190 sq ft minimum may conflict with state law.
- Does a Gorham, Maine ADU need extra parking?
- No. Gorham's off-street parking table requires 2 spaces per single-family home and says accessory dwelling units are exempt.
- Do I have to live on the property if I build an ADU in Gorham, Maine?
- Yes, for now. The owner must live in the main house or the apartment. Maine law bars towns from requiring owner occupancy starting July 1, 2027, so check current rules with Code Enforcement.
Maine's statewide ADU law
Under 30-A M.R.S. §4364-B (first passed as LD 2003 in 2022), a town must allow at least one accessory dwelling unit (ADU) on a lot with a single-family home anywhere homes are allowed. Towns had to comply by 2024.
Rules in effect now:
- It can be inside the house, attached, or a new detached building.
- One ADU per lot is exempt from density limits.
- No extra parking can be required beyond what the house already needs.
- Setbacks are the same as for the house.
- Minimum size: the state building codes board set 160 sq ft in 2025. Towns may set a maximum size.
- Before you can move in, you must show the ADU has adequate water and septic/sewer.
- In the shoreland zone ADUs must meet shoreland rules, but towns can't ban them there outright.
- Sprinklers aren't required unless the ADU is in or attached to a building with more than 2 units.
Coming July 1, 2027 (LD 1829 of 2025, pushed back by LD 2173 in 2026): towns can no longer require the owner to live on the property, ADUs must also be allowed next to 2- and 3-unit buildings, and towns can't require planning board approval for an ADU. Towns may still regulate short-term rentals in ADUs. Private covenants and HOA rules can be stricter.
What the ordinance says
- Sec. 2-4.C Accessory Apartments, Land Use and Development Code – Chapter 2: General Standards of Performance, p. 70
Accessory apartments is a permitted use in all zoning districts which allow single-family dwelling or a lot where a single-family exists, subject to the approval of the Code Enforcement Officer and adherence to the following standards:
- Sec. 2-4.C(1)-(2), Land Use and Development Code – Chapter 2: General Standards of Performance, p. 70
1. The owner(s) of the lot must reside in the principal structure or in the accessory apartments. 2. The number of occupants of any accessory apartment is limited to two.
- Sec. 2-4.C(3), Land Use and Development Code – Chapter 2: General Standards of Performance, p. 70
3. Accessory apartment shall contain up to a maximum of 800 square feet of living space and shall not be less than 190 square feet in area.
- Sec. 2-4.C(4)(b)(2), Land Use and Development Code – Chapter 2: General Standards of Performance, p. 70
2) Accessory apartment detached from the existing single-family dwelling are required to each have a separate and functioning septic system meeting all State and local regulations for septic systems.
- Sec. 2-4.C(8), Land Use and Development Code – Chapter 2: General Standards of Performance, p. 71
Accessory apartment is required to meet the setbacks in the zoning district they are located in and if applicable Shoreland zoning requirements.
- Sec. 2-4.C(9), Land Use and Development Code – Chapter 2: General Standards of Performance, p. 71
9. Only one accessory apartments shall be permitted on a lot.
- Sec. 2-2.A Off-Street Parking Standards (table), Land Use and Development Code – Chapter 2: General Standards of Performance, p. 39
Residential - single-family and 2 parking spaces per dwelling unit. Accessory dwelling units duplex are exempt.