ADU rules in Bangor

Bangor's Land Development Code defines an accessory dwelling unit as a subordinate unit that "may be attached, detached, or contained within an accessory building (e.g., garage) on the lot" (§ 165-13), so a detached backyard cottage or a garage conversion is squarely covered. Section 165-31.2B directs the Code Enforcement Officer to approve an ADU that satisfies eleven listed conditions, and ADUs are named as a permitted use in the three districts that carry Bangor's single-family neighborhoods: Urban Residence 1 (§ 165-88C(5)), Low-Density Residential (§ 165-99C(6)) and Rural Residence and Agricultural (§ 165-105C(15)). One ADU is allowed per lot, and only where a single structure on the lot already holds one to three dwelling units (a single-family home, duplex or triplex). Bangor deleted its old placement restrictions in April 2024 (Ord. No. 24-107): the ban on siting a detached ADU in front of the principal dwelling and the 25-foot height cap on detached ADUs are now reserved and no longer apply.

The same definition in § 165-13 covers a unit "within" the principal dwelling or attached to it, and § 165-31.2B(5) presumes internal conversions by requiring only that an ADU below finished grade in the principal dwelling have a daylight entry. The 2019 rule that barred an attached ADU from connecting to the front of the principal dwelling was repealed in April 2024, so an addition or an internal split may face the street. An attached or internal ADU takes the same administrative Code Enforcement Officer approval as a detached one, and the same 50% or 1,000 square foot cap applies. Manufactured housing, mobile homes and temporary camping vehicles may not be used as an ADU, except that manufactured housing is allowed as an ADU in the Rural Residence and Agricultural District (§ 165-31.2B(7)).

Section 165-31.2B(1) caps an ADU at 50% of the principal dwelling's square footage or 1,000 square feet, whichever is smaller, so a 1,600 square foot house supports an 800 square foot ADU while anything above 2,000 square feet hits the flat 1,000 square foot ceiling. The floor is 160 square feet unless the Technical Building Codes and Standards Board adopts a different minimum under 10 M.R.S. § 9722. There is no separate ADU height limit or setback any more: § 165-31.2B(2) applies the dimensional requirements and setbacks of the principal dwelling, except that where the Code allows a reduced accessory-structure setback that reduced figure controls. The relevant relief is § 165-70D, under which the Code Enforcement Officer may cut the side or rear setback for a freestanding accessory building to as little as five feet, but only in the URD-1, URD-2 and M & SD districts and only after notifying abutters. ADUs are exempt from minimum lot area and units-per-acre requirements (§ 165-31.2A).

Bangor has never required the owner to live on the property, and that is what this answer rests on: neither the eleven conditions in the current § 165-31.2B nor the original text added 12-23-2019 by Ord. No. 20-017 contains an owner-occupancy or primary-residence condition, and nothing else in Chapter 165 imposes one on ADUs. Maine has enacted a preemption but it is not in force yet. 30-A M.R.S. § 4364-B(4)(E), added by PL 2025, c. 385, § 17, provides that a municipality "shall allow the construction or occupancy of an accessory dwelling unit on a lot even if the owner of the lot where the accessory dwelling unit is located does not reside in a dwelling unit on that lot." That Act originally applied on a split schedule, but PL 2025, c. 733, § 25 (LD 2173, approved 4-16-2026) struck the earlier branch, so c. 385 now applies to all municipalities beginning July 1, 2027, and c. 733, § 26 makes that change retroactive to September 24, 2025. Bangor homeowners therefore gain nothing new from the state preemption until July 1, 2027; they simply never needed it, because the City's own ordinance has always been silent. Owner occupancy still matters downstream: a short-term rental counts as "hosted" only when the owner or operator's primary residence is on the premises, and hosted rentals escape the citywide non-hosted cap.

Bangor requires no off-street parking for an ADU, and says so twice. Section 165-31.2A states that ADUs "are not subject to minimum lot area requirements, requirements for the number of dwelling units per acre, nor minimum parking requirements," and the off-street parking article repeats the exemption at § 165-72R(6): "Accessory dwelling units shall be exempt from the requirements of this section." That goes at least as far as the statutory floor in 30-A M.R.S. § 4364-B(4)(C), which bars any ADU parking requirement beyond what the single-family dwelling on the lot already needs. Unlike most of § 4364-B, paragraph (4)(C) was enacted by the original LD 2003 (PL 2021, c. 672, § 6) and has been left untouched by both PL 2025, c. 385 and PL 2025, c. 733, so it has bound Bangor since the LD 2003 implementation date of January 1, 2024 under 30-A M.R.S. § 4364(1-A)(A). There is no conflict to reconcile: the local text is a flat exemption, not a reduced ratio. Parking for the principal dwelling still has to meet the district's own standards.

ADU review in Bangor is administrative: § 165-31.2B provides that "the Code Enforcement Officer shall approve an ADU upon a determination that said ADU complies with the following conditions," a ministerial checklist rather than a discretionary vote. No Planning Board land development permit is triggered, because § 165-111C(2) exempts "any construction of four or fewer dwelling units on a lot" notwithstanding the permit triggers in § 165-111A and B (only a project that creates three or four separate detached structures drops into the lighter minor site plan revision track of § 165-116). A building permit and certificate of occupancy from the Code Enforcement Office are still required, and where the ADU is not on City sewer § 165-31.2B(10) treats it as a separate dwelling unit for septic design. The one discretionary detour is historic: in a historic district, or on a designated historic site or landmark, § 148-8E(1) bars the City from issuing any building or land development permit until the Historic Preservation Commission has issued a certificate of appropriateness.

Long-term tenancy is unrestricted: nothing in § 165-31.2 limits who may rent an ADU or for how long, and Bangor's Rental Registry is an explicitly voluntary Quality Housing Provider pilot rather than a mandatory licence. Short-term renting used to be banned outright, since the 2019 ordinance provided at § 165-31.2B(8) that "ADUs shall not be rented for less than 30 days"; that subsection is now repealed and Chapter 254, adopted 10-23-2023 by Ord. No. 23-308, instead names "an accessory dwelling unit (ADU)" as a licensable short-term rental unit (§ 254-3). A licence costs $250 for a new or third-cycle renewal ($100 otherwise), requires a 24/7 responsive local contact and a fire and life-safety inspection, and expires every May 31. If you live in the house and rent the ADU (or live in the ADU and rent the house), the rental counts as "hosted" and avoids the cap; a non-hosted ADU rental competes for licences capped at 1% of all dwelling units in the City, issued first-come first-served, and no person may hold more than five short-term rental licences citywide. There is no separate-sale or condominium provision for ADUs in Chapter 165, so an ADU cannot be conveyed apart from the lot.