MassHousing Accessory Dwelling Unit (ADU) Loan Program

MassHousing, Massachusetts Housing Finance Agency

Available Home Repair

About This Program

MassHousing Accessory Dwelling Unit (ADU) Loan Program is available to homeowners in Boston, MA.

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.

Verified against MassHousing, Massachusetts Housing Finance Agency's official page on 2026-06-17.

Data last verified 2026-04-03. How we verify our data.

In Boston, MA, you can combine this program with other local help to cut your cost:

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

Get free help applying Visit Official Program Page Track this program

617-854-1000

A grant-savvy contractor in Boston, MA can handle the paperwork, inspections, and timelines so your funding releases on schedule. Getting matched is free.

You will likely need a contractor to apply

Projects like this almost always need a licensed contractor, and many grants ask for a written estimate as part of your application. Lining up a contractor in Boston early keeps your application moving.

Get matched with a contractor

Each program sets its own contractor rules. Check the official program page for exact requirements.

Your application paperwork

Documents you will likely need

  • Proof you own and live in the home (deed, recent mortgage statement, or property tax bill).
  • A government-issued photo ID for every owner on title.
  • Household income proof (recent pay stubs, last year's tax return, or benefit award letters for everyone in the home).
  • A written estimate from a licensed contractor for the work (many programs require this to apply).
  • Photos of the problem area or the work to be done.
  • The program's own application form, completed (use the official link or phone number on this page).
Download this checklist (PDF)

Requirements vary by program and locality. Confirm the exact rules on the official program page. We can help you prepare your paperwork, but you submit it yourself.

Deadline: Launched January 2026, rolling applications

Questions about this program?

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Frequently asked questions

How much can MassHousing Accessory Dwelling Unit (ADU) Loan Program provide in Boston, MA?

Up to $250,000 (detached ADU).

Who qualifies for MassHousing Accessory Dwelling Unit (ADU) Loan Program in Boston?

MassHousing Accessory Dwelling Unit (ADU) Loan Program is open to homeowners in Boston, MA.

How do I apply for MassHousing Accessory Dwelling Unit (ADU) Loan Program in Boston, MA?

Apply directly with MassHousing, Massachusetts Housing Finance Agency using the official program link on this page or call 617-854-1000. There is no middleman and no fee. Deadline: Launched January 2026, rolling applications.

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