ADU Rules in Lewiston, Maine

Lewiston is the Androscoggin County seat and Maine's second-largest city, with a population of about 38,000 on the eastern bank of the Androscoggin River. Paired with Auburn (across the river) as the "Twin Cities," Lewiston has a significant Franco-American heritage from its 19th-century textile mill era. The city's historic mill buildings along the Androscoggin have been undergoing major redevelopment. Lewiston and Auburn are entirely separate cities. Maine has no statewide ADU preemption law — Lewiston's local zoning governs.

Lewiston vs. Auburn

• Lewiston: East bank of the Androscoggin River — use Lewiston's permit process
• Auburn: West bank — separate city, separate zoning ordinance
• Permits from Auburn are not valid in Lewiston

Lewiston Zoning Ordinance

The City of Lewiston Zoning Ordinance governs all land use within Lewiston city limits.

Permitted ADU Types

Depending on the zoning district:

• Accessory apartments: Within or attached to primary structure
• Detached accessory dwelling units: Subject to zoning standards

Verify current ADU provisions with Lewiston's Planning Division.

Size Limits

Accessory dwelling units are subject to:

• Maximum floor area per zone
• Lot coverage restrictions

Setbacks

Per Lewiston residential zone (typical):

• Rear: Minimum setback
• Side: Minimum setback

Maine Shoreland Zoning

Properties within 250 feet of the Androscoggin River or other water bodies are subject to Maine's Shoreland Zoning Act (Title 38). The Androscoggin River runs along Lewiston's western edge — verify shoreland zoning for riverfront properties.

Androscoggin River Flood Zones

Parts of Lewiston near the Androscoggin River may be in FEMA flood zones. Verify flood map status.

Historic Districts

Lewiston has historic mill buildings and residential districts. Properties in historic districts may require review for exterior modifications.

Permit Process

1. Verify jurisdiction: Confirm your property is in Lewiston (not Auburn)
2. Verify zoning: Lewiston Planning Division
3. Check shoreland zoning: If near the Androscoggin River
4. Check flood zone status: If near the river
5. Historic review: If in a historic district
6. Submit plans: Lewiston Building Division
7. Building permit and inspections
8. CO: Required before occupancy

Contact

City of Lewiston Planning Division 27 Pine Street, Lewiston, ME 04240 Phone: (207) 513-3125 Website: lewistonmaine.gov

Disclaimer: Maine has no statewide ADU law. Lewiston and Auburn are separate cities. Verify current ADU allowances with the City of Lewiston before starting any project.