ADU rules in Sanford

A new detached structure is one of the three configurations the ordinance expressly allows, and § 280-15-13B(1) opens ADUs to 'any zone which allows residential uses.' The Table of Land Uses backs that up, listing an accessory dwelling unit as a use permitted by right ('P') in all four zones that allow single-family detached dwellings: Rural Residential (RR), Rural Mixed Use (RMU), Residential Development (RD) and Urban (U). Inside the Growth Zone of the Comprehensive Plan a parcel may carry up to two ADUs; everywhere else, one. Renovating an existing freestanding building into an ADU counts as the same configuration, and the ADU otherwise follows the underlying zone's setback, height and coverage standards because § 280-15-13B(2) hands anything the ADU section does not specify back to the zone.

Interior conversions and additions are both listed configurations: an ADU may use 'space within the interior of an existing dwelling,' or be an addition made part of the principal structure, or be joined to it by a breezeway of up to 20 feet. Sanford is unusually generous about what the ADU may attach to: the principal dwelling structure may be a single-family dwelling, a two-family dwelling, or a multifamily dwelling with fewer than five units. Carving an ADU out of a preexisting nonconforming structure is permitted so long as it does not increase the nonconformity and meets the rest of Chapter 280.

§ 280-15-13C(4) caps an ADU at 40% of the living area of the principal dwelling structure or 1,000 square feet, 'whichever is greater,' so 1,000 square feet is a floor rather than a ceiling: a 4,000 sq ft house supports a 1,600 sq ft ADU, while a small cottage still gets a full 1,000. Bedrooms are capped at three. There is no ADU-specific height, setback or lot-coverage number; § 280-15-13B(2) applies the standards of the zone the ADU sits in and B(3) keeps overlay-zone regulations in force. Maine sets a 190 sq ft statutory minimum and expressly permits municipalities to impose a maximum, so Sanford's cap is within the state framework.

The owner must live in either the principal dwelling structure or the ADU, must file a written statement with the Code Enforcement Officer saying which one, and continued occupancy of the ADU after a sale or transfer is conditioned on the new owner agreeing to the same requirement. This is currently lawful and enforceable. The version of Maine's ADU mandate that applies to municipalities today is silent on owner occupancy, and the statutory ban in 30-A M.R.S. § 4364-B(4)(E), though already printed on the Revisor's codified page, does not reach any Maine municipality until July 1, 2027. Treat Sanford's requirement as live now and re-check it after that date.

§ 280-15-13C(6) says flatly that 'there are no off-street parking requirements for an ADU'; if an owner chooses to stripe spaces anyway, those spaces must meet the general off-street parking standards of § 280-14-12. Sanford wrote this in on January 16, 2024, in the same amendment that conformed the ADU section to LD 2003, matching the state bar on ADU-specific parking in 30-A M.R.S. § 4364-B(4)(C), which has bound the city since the January 1, 2024 implementation date. There is no conflict between the two texts here. The one place parking resurfaces is short-term rental licensing: a licensed short-term rental must document sufficient on-site parking and may not use street parking.

Administrative, with a staff escalation valve. The Table of Land Uses marks an accessory dwelling unit 'P', permitted by right, in RR, RMU, RD and U, so no conditional use permit and no Planning Board hearing is required. The Code Enforcement Officer, with the concurrence of the Planning Director, makes the finding that the project meets § 280-15-13, and construction proceeds on an ordinary building permit that the CEO must approve, deny or refer within seven days of filing. The CEO 'may elevate the review of ADU application based on the size or complexity of the project' into the site plan review track of § 280-16-5, where small projects still land with staff rather than a board, and an applicant who objects to a buffering or landscaping condition may ask the Planning Board to look at it.

Chapter 280 puts no limit on renting an ADU out, but it does require the principal dwelling and the ADU to stay in one ownership and forbids selling the ADU separately from the house. Any rental, long or short, needs an annual rental housing license from the Code Enforcement Office under Chapter 149, Article V: licenses expire December 31, fees run by unit count with a $100 deduction for each owner-occupied unit, and at least $500,000 of liability and property insurance must be documented or the fee doubles. A short-term rental is a let of under 30 days. In the Urban Zone and the Residential Development Zone § 149-5.18A requires the short-term rental to be the owner's primary residence and caps a single-family property at one short-term rental unit (or two rooms as a guest home), a test that reads awkwardly against an ADU rented out while the owner lives in the main house; the Rural Residential and Rural Mixed Use zones carry no primary-residence test. Occupancy is capped at two adults per bedroom and on-site parking must be documented.