ADU Rules in Lynn, MA
Lynn 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
R1 — Two Family Residential
Single-family and two-family dwellings at low density
| 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 |
R2 — Medium Density Residential
Single-family, two-family, and multifamily (triple-deckers, small apartment buildings)
| 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 |
R3 — High Density Residential
Higher density multifamily residential, apartment buildings
| Type | Approval | Max Size | Height | Parking | Owner Occ. |
|---|---|---|---|---|---|
| Detached ADU | By Right | 900 sq ft | 40 ft | 1 space | No |
| Attached ADU | By Right | 900 sq ft | 40 ft | 1 space | No |
| Interior Conversion | By Right | 900 sq ft | 40 ft | 1 space | No |
R4 — High Rise Residential
High-rise apartment buildings, highest density residential. Minimum 3 stories.
| Type | Approval | Max Size | Height | Parking | Owner Occ. |
|---|---|---|---|---|---|
| Detached ADU | By Right | 900 sq ft | 75 ft | 1 space | No |
| Attached ADU | By Right | 900 sq ft | 75 ft | 1 space | No |
| Interior Conversion | By Right | 900 sq ft | 75 ft | 1 space | No |
Transit Stations
Properties near transit stations may qualify for parking exemptions.
Lynn
Lynn Interim
River Works
Building Department
Explore ADU Topics in Lynn
ADU Zoning in Lynn, MA
ADU Permit Process in Lynn, MA
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ADU Size Limits in Lynn, MA
ADU Setback Requirements in Lynn, MA
ADU Parking Requirements in Lynn, MA
ADU Types Explained in Lynn, MA
ADU Financing in Lynn, MA
ADU Timeline in Lynn, MA
ADU Property Value Impact in Lynn, MA
ADU Rental Income in Lynn, MA
Frequently Asked Questions
Are ADUs allowed by right in Lynn, MA?
Yes. ADUs in Lynn 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 Lynn?
Lynn 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 Lynn?
No. Lynn 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 Lynn, MA?
In Lynn, 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 Lynn have historic district rules for ADUs?
Yes. Lynn has historically significant areas including Central Square Historic District, High Rock Tower, Lynn Armory, Mary Baker Eddy Historic House, The Museum at Lynn Museum & Arts Center. 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 Lynn?
Yes, long-term rentals are allowed for ADUs in Lynn. However, short-term rentals (like Airbnb) are not currently allowed for ADUs. With a population of 101,253, Lynn has strong rental demand.