MassHousing Accessory Dwelling Unit (ADU) Loan Program

About This Program

Launched in January 2026, this MassHousing program finances ADU construction as a fixed-rate second mortgage for single-family homeowner-occupants earning up to 135% AMI. Detached ADUs can receive up to $250,000; attached ADUs up to $150,000. The loan is structured with a 5.25% interest rate portion amortized over 20 years, plus a supplemental 0% deferred component, making part of the financing effectively interest-free.

Detached ADU: up to $250,000; attached ADU: up to $150,000. 5.25% fixed + 0% deferred portion. 20-year amortization. Income limit: 135% AMI. Must have permits ready.

Key Details

• Finances ADU construction, up to $250,000 detached or $150,000 attached
• Structured as 5.25% fixed-rate + 0% deferred second mortgage
• 20-year amortization; income limit is 135% AMI
• Must own and occupy a single-family home; permits must be in hand
• Learn more and find participating lenders at masshousing.com/adu

How to Apply

Deadline: Launched January 2026, rolling applications