Boston
Suffolk County · Pop. 675,647
Boston has approved 44 of 69 ADU applications (64% approval rate) and has 5 of 10 bylaw provisions consistent with state law.
Based on 44 approved ADU applications and 675,647 residents
Permits
69 applications since the ADU law took effect in Feb 2025
Bylaw Consistency
Boston is exempt from the state ADU law entirely — it’s the only municipality in Massachusetts that doesn’t operate under G.L. c. 40A. Owner-occupancy is required and workshop attendance is mandatory, but internal, attached, and detached ADUs are all allowed. The zero-interest loan program (up to $50K for income-eligible homeowners) is a genuine advantage.
Provision-by-provision analysis available
We've mapped 10 provisions in Boston against Chapter 150. See which specific bylaw sections appear inconsistent with state law.
See full compliance analysisCost Snapshot
No cost data available yet for Boston.
Try the cost estimatorADU Impact on Housing Production
In 2024, Boston issued 1,789 total residential building permits. In the first year of the ADU law, 44 ADU permits were approved — equivalent to 2.5% of prior-year housing production.
Source: Census Bureau (2024) via UMass Donahue Institute; EOHLC ADU Survey (2025)
How Boston Compares
Next Steps
Sources: EOHLC ADU Survey 2025. Population estimates from 2024 Census ACS.
Disclaimer: ADU Pulse provides data for informational purposes only. It does not constitute legal, financial, or construction advice.Bylaw consistency analysis reflects our interpretation of public records and may not reflect the most current local amendments.
See methodology for details on data collection, scoring, and consistency analysis.