ADU Rules in Quincy, Massachusetts

Quincy is a Norfolk County city of about 103,000 immediately south of Boston on the shore of Boston Harbor. Birthplace of Presidents John Adams and John Quincy Adams (Adams National Historical Park is in Quincy), Quincy is a major Boston suburb with extensive coastline along Quincy Bay. The city has been growing rapidly with transit-oriented development near its MBTA Red Line stations. Massachusetts enacted a statewide ADU law (Chapter 150, Acts of 2024) requiring ADUs by right in single-family zones.

Massachusetts Statewide ADU Law (2024)

Massachusetts Chapter 150, Acts of 2024 requires municipalities to allow ADUs by right in single-family residential zoning districts. Verify how Quincy has implemented this law.

Quincy Zoning Ordinance

The City of Quincy Zoning Ordinance governs all land use in Quincy city limits.

Permitted ADU Types

Per Massachusetts ADU law and Quincy zoning (verify current standards):

• Basement and interior conversions: Common in Quincy's dense residential stock
• Attached ADUs: With separate entrance
• Detached ADUs: In eligible zones

Size Limits

Per Massachusetts ADU law:

• ADU cannot exceed smaller of: primary dwelling or 900 square feet

Setbacks

Per Quincy residential zone:

• Rear: Minimum setback
• Side: Minimum setback

Massachusetts Chapter 91 — Coastal Waterways

Quincy has extensive tidelands along Quincy Bay, the Fore River, and Boston Harbor. Massachusetts Chapter 91 (Waterways Act) governs tidelands. Properties near tidal waters require Chapter 91 review. The Massachusetts Coastal Zone Management (CZM) program also applies to coastal areas.

Coastal Flood Zones

Quincy's coastal location means significant FEMA coastal flood zone exposure. Verify flood map status for all coastal and low-lying properties. Coastal flood zones require elevated construction standards.

Massachusetts Wetlands Protection Act

Properties within 100 feet of wetlands, tidal flats, or 200 feet of rivers are subject to the Massachusetts Wetlands Protection Act. Quincy Conservation Commission review required.

Adams National Historical Park

The Adams NHP is a federal National Park site — it does not affect civilian residential ADU rules. Surrounding residential properties use Quincy's Zoning Ordinance.

MBTA Communities — Red Line

Quincy has three MBTA Red Line stations (Quincy Center, Quincy Adams, North Quincy). MBTA Communities law requires multifamily zoning near these stations.

Permit Process

1. Verify zoning and state ADU law: Quincy Dept. of Inspectional Services
2. Chapter 91 review: If near tidal waterways or Boston Harbor
3. Conservation Commission review: If near wetlands or tidal areas
4. Check flood zone: Coastal flood zones require elevated construction
5. Submit plans: Quincy Building Division
6. Building permit and inspections
7. CO: Required before occupancy

Contact

City of Quincy Department of Inspectional Services 1305 Hancock Street, Quincy, MA 02169 Phone: (617) 376-1160 Website: quincyma.gov

Disclaimer: Massachusetts statewide ADU law (2024) applies. Coastal flood zones and Chapter 91 waterway restrictions apply to many Quincy properties. Verify current standards before starting any project.