Maine state law: ADU statute preempts owner-occupancy mandate; otherwise local

The Maine Revised Statutes do not require that a short-term rental be the operator's primary residence at the state level. Whether STRs are limited to owner-occupied (primary-residence) units is set by municipal ordinance under 30-A MRS § 3001 home-rule authority. Portland's STR program distinguishes between owner-occupied (no district cap) and non-owner-occupied (district caps) registrations; Bar Harbor restricts non-owner-occupied STRs by license category. Importantly, 30-A MRS § 4364-A (enacted by LD 2003, PL 2021 ch. 672) expressly PREEMPTS municipalities from requiring owner-occupancy of either the primary dwelling or an accessory dwelling unit ('A municipality may not require owner-occupancy of either the principal dwelling unit or the accessory dwelling unit'). This means that a Maine municipality cannot use an owner-occupancy mandate to prevent an ADU from being used as an STR, although it can otherwise regulate STR use of the ADU. The 36 MRS § 1811 lodging-tax framework treats all stays under 28 days the same regardless of whether the property is the host's primary residence.

Municipal STR-permit revocation and fines for non-owner-occupied STR operating in violation of a local primary-residence ordinance; no state-level penalty.