ADU Rules in Quincy, MA
Quincy follows the Massachusetts state baseline with local regulations.
State Baseline: Affordable Homes Act
Up to 900 sq ft or 50% of principal dwelling (whichever is smaller). By-right approval statewide.
Zoning Districts
RES-A — Residence A
Single Family Residential
| Type | Approval | Max Size | Height | Parking | Owner Occ. |
|---|---|---|---|---|---|
| Detached ADU | By Right | 900 sq ft | 35 ft | 1 space | No |
| Attached ADU | By Right | 900 sq ft | 35 ft | 1 space | No |
| Interior Conversion | By Right | 900 sq ft | 35 ft | 1 space | No |
RES-B — Residence B
Multifamily Low Density Residential (1-3 units base tier)
| Type | Approval | Max Size | Height | Parking | Owner Occ. |
|---|---|---|---|---|---|
| Detached ADU | By Right | 900 sq ft | 35 ft | 1 space | No |
| Attached ADU | By Right | 900 sq ft | 35 ft | 1 space | No |
| Interior Conversion | By Right | 900 sq ft | 35 ft | 1 space | No |
RES-C — Residence C
Multifamily Medium Density Residential
| Type | Approval | Max Size | Height | Parking | Owner Occ. |
|---|---|---|---|---|---|
| Detached ADU | By Right | 900 sq ft | 60 ft | 1 space | No |
| Attached ADU | By Right | 900 sq ft | 60 ft | 1 space | No |
| Interior Conversion | By Right | 900 sq ft | 60 ft | 1 space | No |
RES-D — Residence D
Multifamily High Density Residential
| Type | Approval | Max Size | Height | Parking | Owner Occ. |
|---|---|---|---|---|---|
| Detached ADU | By Right | 900 sq ft | 60 ft | 1 space | No |
| Attached ADU | By Right | 900 sq ft | 60 ft | 1 space | No |
| Interior Conversion | By Right | 900 sq ft | 60 ft | 1 space | No |
Transit Stations
Properties near transit stations may qualify for parking exemptions.
North Quincy
Quincy
Quincy Adams
Quincy Center
Wollaston
Building Department
Explore ADU Topics in Quincy
ADU Zoning in Quincy, MA
ADU Permit Process in Quincy, MA
ADU Costs in Quincy, MA
ADU Size Limits in Quincy, MA
ADU Setback Requirements in Quincy, MA
ADU Parking Requirements in Quincy, MA
ADU Types Explained in Quincy, MA
ADU Financing in Quincy, MA
ADU Timeline in Quincy, MA
ADU Property Value Impact in Quincy, MA
ADU Rental Income in Quincy, MA
Frequently Asked Questions
Are ADUs allowed by right in Quincy, MA?
Yes. ADUs in Quincy are approved by right — you submit your plans to the building department and receive a building permit without a public hearing or special permit process. This is guaranteed by the Affordable Homes Act.
What types of ADUs can I build in Quincy?
Quincy allows detached, attached, conversion ADUs. With up to 900 sq ft allowed, a detached ADU gives you the most flexibility for a full living space.
Do I need to live on the property to build an ADU in Quincy?
No. Quincy does not require owner occupancy — this is a right guaranteed by the Affordable Homes Act. You can rent both your main home and the ADU, making this a pure investment property if you choose.
How big can I build an ADU in Quincy, MA?
In Quincy, you can build an ADU up to 900 square feet or 50% of your home's living area, whichever is larger. With 900 sq ft, you have enough room for a full 2-bedroom cottage with a kitchen, bathroom, and living area. This is guaranteed by the Affordable Homes Act.
Does Quincy have historic district rules for ADUs?
Yes. Quincy has historically significant areas including Adams National Historical Park, Downtown Quincy Historic District, Faneuil Hall Marketplace, Quincy Historical Society & Museum, Quincy Quarries Reservation. If your property is in or near a historic district, your ADU design may require review by the local historical commission for architectural compatibility. This can affect timelines and design choices.
Can I rent out my ADU in Quincy?
Yes, long-term rentals are allowed for ADUs in Quincy. However, short-term rentals (like Airbnb) are not currently allowed for ADUs. With a population of 101,636, Quincy has strong rental demand.