The ADU Exchange
The ADU Exchange University
The ADU Exchange University

Everything the new ADU law changed, explained one question at a time.

Sourced, plain-English guides for homeowners, families, REALTORS®, lenders, and the trades. Filed by department, so the answer sits next to the professionals who act on it.

14 guides · Five departments · Every claim traced to statute, agency guidance, or published research

How the University is organized


The ADU Exchange is built as departments, and so is the University. Each guide is filed where its subject lives: septic and contractor questions with the Trades, financing in the Bank Vault, law and ownership in the Court House, transaction questions with Real Estate, and accessibility and aging in place in Accessories. When a guide belongs in two places, it appears in both.

The ADU Exchange is an education and connection platform. We do not build, permit, finance, or insure ADUs, and nothing here is legal, tax, or financial advice. Where a guide points to a decision, it also points to the licensed professional who should make it with you.

Department

Trades

Site feasibility, contractor selection, and the work itself.

Visit the Trades department →
Septic and site feasibility

Title 5 First: The Septic Question That Decides Every Massachusetts ADU

On septic lots the ground casts the deciding vote. How Title 5 bedroom math works, what happens at time of sale, and the one question to raise when a system needs replacing anyway.

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Contractor due diligence

It Is Coming Here: What California's ADU Fraud Wave Should Teach Every New England Homeowner

Hundreds of families lost tens of millions to builders who took deposits and built nothing. Why the safety nets failed, and how to protect a deposit in all six New England states.

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Department

Bank Vault

Financing the build and qualifying for the loan.

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FHA 203(k) and qualifying income

Making the First Mortgage Work: How an ADU and a 203(k) Loan Can Change a Young Couple's Math

FHA now lets a portion of ADU rental income count toward qualifying, and 203(k) can finance the renovation that creates the unit. What the rules say, what they do not, and the questions to bring to a lender.

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Department

Court House

Law, zoning, ownership, permitting, and rental rules.

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The law, explained

The New Rules of the Backyard: What the Massachusetts ADU Law Actually Says, in Plain English

One ADU by right on single family lots since February 2, 2025. The 900 square foot rule, what towns can and cannot require, and what the law leaves alone.

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Zoning math

The Basement Counts: How Gross Floor Area Decides the Size of Your Massachusetts ADU

An unfinished basement with compliant ceiling height is part of Gross Floor Area under 760 CMR 71.02. On a modest house that is the difference between a 500 square foot studio and a 900 square foot unit.

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Ownership and title

Whose Name Goes on the Deed? Settle It Before the Floor Plan

Building for your parents? Four ways Massachusetts families structure ownership, and the tradeoffs of each.

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Elder law and MassHealth

The Five Year Look-Back: What MassHealth Can and Cannot Do to Your ADU Investment

Parents contributing to an ADU on a child's property face the look-back if long term care is ever needed. What the rule reviews, gift versus purchase, and why the paperwork comes first.

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Rental law

Mid-Term Rentals and Your ADU: Why 30 Days Is the Wrong Number

In Massachusetts a 30-day lease is a short-term rental by statute, the one category towns may prohibit outright. The 31-day cliff, the excise, and why 13 weeks is the number that works.

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Department

Real Estate

What ADU potential means on both sides of the transaction.

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For REALTORS®

The Question On Every Listing Appointment You Are Not Ready For

ADU capability is now a pricing input, a marketing asset, and a disclosure exposure on every single family listing. Why agents need an Ecosystem rather than a vendor.

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Transaction clarity

ADU Potential Is Now Part Of Your Transaction: A Guide For Buyers And Sellers

What sellers must substantiate before advertising ADU potential, and what buyers must verify before paying for it.

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Checklist

The Five Documents That Decide ADU Potential

A one-page checklist of the five papers that determine whether a Massachusetts property can support an ADU. For sellers before they list and buyers inside their contingency period.

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For REALTORS® and association leaders

Speaking ADU: The Language Every REALTOR® Will Need for the Next Decade

Massachusetts needs 222,000 homes by 2035 and ADU rights are statewide law. Why speaking ADU is becoming core competence for agents and associations.

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Households and demand

The Launch Pad: One in Three Young Adults Lives at Home, and the Backyard Can Change What That Means

Nearly half of adults under 30 live with their parents. Why the childhood bedroom fails both generations, and how an ADU turns staying home into launching from home.

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Aging in place and accessibility

Aging in Place Is the Biggest Client Conversation of the Next Decade

Three quarters of adults 50 and older want to stay home as they age, and by 2034 older adults will outnumber children. What AARP, Harvard, and the Census Bureau mean for the ADU conversation.

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Department

Accessories

Accessibility, aging in place, solar, and smart home.

Visit the Accessories department →
Aging in place and accessibility

Aging in Place Is the Biggest Client Conversation of the Next Decade

Three quarters of adults 50 and older want to stay home as they age, and by 2034 older adults will outnumber children. What AARP, Harvard, and the Census Bureau mean for the ADU conversation.

Read the article

The editorial standard

Every statistic is sourced and every legal claim traces to the statute, regulation, or agency guidance that governs it. No invented numbers, no investor hype, no advice we are not licensed to give. New guides are added to this catalog and to their department page at the same time.

Ready to move from reading to building?

The Ecosystem connects you with the REALTORS®, lenders, attorneys, and trade professionals each of these guides eventually points to.

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