ADU Rules in Biddeford, Maine

Biddeford is York County's largest city with a population of about 22,000 on the eastern bank of the Saco River in southern Maine. Paired with Saco (across the river) as the "Twin Cities of York County," Biddeford has a historic mill district that has been undergoing significant revitalization, converting 19th-century textile mill buildings to housing, arts, and commercial uses. Biddeford and Saco are entirely separate cities. Maine has no statewide ADU preemption law — Biddeford's local zoning governs.

Biddeford vs. Saco

• Biddeford: East bank of the Saco River — use Biddeford's permit process
• Saco: West bank — separate city, separate zoning ordinance
• Permits from one city are not valid in the other

Biddeford Zoning Ordinance

The City of Biddeford Zoning Ordinance governs all land use within Biddeford 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 Biddeford's Planning Department.

Size Limits

Accessory dwelling units are subject to:

• Maximum floor area per zone
• Lot coverage restrictions

Setbacks

Per Biddeford residential zone (typical):

• Rear: Minimum setback
• Side: Minimum setback

Maine Shoreland Zoning

Properties within 250 feet of the Saco River, Atlantic Ocean shoreline, or other water bodies are subject to Maine's Shoreland Zoning Act (Title 38). Biddeford has Atlantic coastal areas (Biddeford Pool, Hills Beach) — verify shoreland zoning for any coastal or riverfront property.

Coastal and Tidal Areas

Biddeford has Atlantic Ocean coastal areas subject to additional shoreland and wetland restrictions. Verify coastal status for properties near the ocean.

Historic Mill District

Biddeford's downtown mill district is undergoing major renovation. Check current zoning status and historic designation requirements for mill-area properties.

Permit Process

1. Verify jurisdiction: Confirm your property is in Biddeford (not Saco)
2. Verify zoning: Biddeford Planning Department
3. Check shoreland zoning: If near the Saco River or Atlantic coast
4. Submit plans: Biddeford Building Department
5. Building permit and inspections
6. CO: Required before occupancy

Contact

City of Biddeford Planning Department 205 Main Street, Biddeford, ME 04005 Phone: (207) 284-9115 Website: biddefordmaine.org

Disclaimer: Maine has no statewide ADU law. Biddeford and Saco are separate cities. Maine Shoreland Zoning applies near the Saco River and Atlantic coast. Verify current ADU allowances with the City of Biddeford before starting any project.