ADU Rules in Marshfield, MA
Marshfield follows the Massachusetts state baseline with local regulations.
State Baseline Only
This page uses Massachusetts state baseline rules. Local setbacks, height limits, and other dimensional standards may vary. Contact your local building department for specifics.
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 — Default Residential
Default residential zone (state baseline only — specific district not yet researched)
| Type | Approval | Max Size | Height | Parking | Owner Occ. |
|---|---|---|---|---|---|
| Detached ADU | By Right | 900 sq ft | — | 1 space | No |
| Attached ADU | By Right | 900 sq ft | — | 1 space | No |
| Interior Conversion | By Right | 900 sq ft | — | None | No |
Building Department
Explore ADU Topics in Marshfield
ADU Zoning in Marshfield, MA
ADU Permit Process in Marshfield, MA
ADU Costs in Marshfield, MA
ADU Size Limits in Marshfield, MA
ADU Setback Requirements in Marshfield, MA
ADU Parking Requirements in Marshfield, MA
ADU Types Explained in Marshfield, MA
ADU Financing in Marshfield, MA
ADU Timeline in Marshfield, MA
ADU Property Value Impact in Marshfield, MA
ADU Rental Income in Marshfield, MA
Frequently Asked Questions
Are ADUs allowed by right in Marshfield, MA?
Yes. ADUs in Marshfield 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 Marshfield?
Marshfield 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 Marshfield?
No. Marshfield 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 Marshfield, MA?
In Marshfield, 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 Marshfield have historic district rules for ADUs?
Yes. Marshfield has historically significant areas including Hatch Mill, Marcia Thomas House, Marshfield Town Hall, The Daniel Webster Estate & Heritage Center, Winslow House. 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 Marshfield?
Yes, long-term rentals are allowed for ADUs in Marshfield. However, short-term rentals (like Airbnb) are not currently allowed for ADUs.
How accurate is the ADU data for Marshfield?
The information on this page reflects Massachusetts state baseline rules under the Affordable Homes Act. Marshfield may have additional local requirements that differ from the state baseline. We recommend confirming with your local building department before starting your project.