Plain-English answers to common homeowner questions, taken from Portland's published ordinances, with every rule linked to the section it comes from.
Last reviewed
Accessory Dwelling Units (ADUs) Yes. Portland allows up to two ADUs on any lot with a legal residential use. An ADU can be inside the house, an addition, or a new detached building, and it can be up to 2/3 the size of the main unit. Detached ADUs can be 18 feet tall (25 feet over a garage), can't sit between the house and the front lot line, and need no parking. You'll need a building permit; we found no owner-occupancy requirement in the Land Use Code.Allowed with a permit
Backyard Chickens Yes. Portland lets residents keep up to 6 hens per lot (no roosters), for personal use only. Hens must stay in a covered pen during the day and in a henhouse at night. The henhouse goes in the rear yard, at least 10 feet from homes and other structures on neighboring lots, and must meet accessory-structure setbacks. The city repealed its chicken permit in 2017.Allowed
Short-Term Rentals (Airbnb / VRBO) Only if the home is your primary residence. On the mainland, a single-family home can be a short-term rental (under 30 days) only if it is owner-occupied or tenant-occupied with the owner's permission. Every unit must be registered with Permitting & Inspections each year; the first owner-occupied unit costs $100. Non-owner-occupied units are capped citywide, ADUs count as non-owner-occupied (newly built ADUs are exempt from the cap for 5 years), and new tenant-occupied registrations stopped in 2026.Restricted
Fences In Portland's residential zones, a fence or wall within 15 feet of the street can be no more than 4 feet tall unless it sits in the side or rear yard. The Land Use Code sets no height cap for side and rear yards and doesn't require fences to meet setbacks; on corner lots, keep anything in the 25-foot corner sight triangle under 3½ feet. We found no rule saying whether a fence needs a permit, so ask Permitting & Inspections before you build.Allowed
Sheds & Accessory Buildings Yes, but plan on a permit: Portland's building chapter requires one before you build any building or structure, with no small-shed exemption in the city text. In the residential neighborhood (RN) zones, a detached shed with a footprint of 250 sq ft or less needs only 5 feet from the rear line and 3 to 5 feet from the side lines, depending on the zone. Detached accessory buildings can be up to 18 feet tall.Allowed with a permit
Burn Permits & Backyard Fires Campfires in Portland need a valid burning permit. A recreational fire appliance (the code doesn't define it, but it generally means a manufactured fire pit or chiminea) or a fixed outdoor fireplace needs no city permit, but it must sit at least 15 feet from all structures, combustible material and property lines, and open fire rings don't get this exemption. Burning trash or other solid waste is illegal. The city code does not separately address brush burning.Allowed with a permit
Home-Based Businesses Yes. Portland allows home occupations as an accessory use if the business stays incidental to the home and meets the code's standards. Up to 2 nonresident employees may work on site, signs are limited to one unlit sign of 2 sq ft, and clients may visit only from 7 a.m. to 8 p.m. Remote work, and businesses with no employees, no customers and no outside impacts, aren't home occupations and are exempt.Allowed
Swimming Pools Yes, with a permit. Portland's Land Use Code keeps outdoor pools out of the front yard and requires every part of the pool to be at least 10 feet from the house and 10 feet from the side and rear lot lines. Building a structure needs a permit from Permitting & Inspections. Pool fencing and barrier rules weren't in the documents we reviewed.Allowed with a permit
Building Near the Water (Shoreland Zoning) Portland's Shoreland Overlay Zone covers land within 250 feet of rivers, tidal (coastal) wetlands and freshwater wetlands, and within 75 feet of streams. In residential areas, new houses and accessory structures must be at least 75 feet from the water or wetland edge. You can't expand any part of a building within 25 feet of the water. Near the water, clearing is limited to openings of 250 sq ft or less, and non-vegetated surfaces can cover at most 20% of the shoreland part of your lot. Work needs a permit from the Building Authority.Allowed with a permit
Docks, Piers & Floats Possibly, with permits. Portland's shoreland rules allow one pier, dock or wharf per lot outside the working-waterfront zones. It must be no bigger than needed and needs no water setback. A new permanent structure over the water also needs a Maine DEP permit and may need Army Corps of Engineers and Portland Harbor Commission approval. We didn't have the Harbor Commission's rules, so mooring and harbor-channel requirements aren't covered here.Allowed with a permit