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.
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 Proficiency Series runs through every department: one guide per profession on what it means to be ADU proficient, built on the same four-part standard (jurisdiction literacy, craft adaptation, handoff fluency, honest limits). Proficiency is an editorial standard for discussing practice, not a license, certification, or endorsement, and membership in the Ecosystem does not certify competence.
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.
Site feasibility, contractor selection, and the work itself.
Feasibility before the quote, a contract that survives the site, permit sequencing from zoning to certificate of occupancy, draws that match the lender, and the six-state consumer protection laws a proficient GC knows by name.
Read the articleThe dwelling-unit core every trade shares, how electrical, plumbing, HVAC, site work, septic, framing, and inspection each change on a second dwelling, and who is licensed to do what in all six states.
Read the article"Instrument survey" names a tool, not a product. What a survey establishes, what it never will, how to buy the right scope in all six states, and the order of operations that keeps a family from designing a building that cannot be placed.
Read the articleWater, sewer, and electrical connections are the ADU costs nobody advertises, and every one of them is knowable before you commit. The fee schedules, the sequence, and the questions that make an estimate honest.
Read the articleOn 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.
Read the articleHundreds 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.
Read the articleFinancing the build and qualifying for the loan.
There is no ADU loan; there is a product map. As-completed appraisals, draws, what MassHousing and RIHousing actually offer, why New Hampshire has no state program, and the RESPA and licensing lines a proficient lender never crosses.
Read the articleUsing a HECM reverse mortgage to build an accessory dwelling unit: the first-year cap, the real costs, the rules that bite a borrower who builds, and every alternative compared.
Read the articleFHA 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.
Read the articleLaw, zoning, ownership, permitting, and rental rules.
One generation's money, another generation's land, and a promise nobody wrote down. The five events every family ADU will meet, why a parent can become a tenant, and the order of operations that puts the attorney before the drawings.
Read the articleOther structures coverage defaults to ten percent of the house. A detached ADU can cost half the house. The seven questions to get answered in writing, and the three moments the agent belongs on the team.
Read the articleZoning, title, estate planning, family law, and landlord-tenant practice on one lot, plus the three insurance questions a homeowner does not know to ask: is the structure covered, is the build covered, and is the replacement cost still right.
Read the articleMost ADU projects that fail do not fail over budgets or permits. They fail over inheritance conversations nobody scheduled and septic capacity nobody checked. The two risks to resolve first, and the order to resolve them in.
Read the articleOne 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.
Read the articleAn 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.
Read the articleBuilding for your parents? Four ways Massachusetts families structure ownership, and the tradeoffs of each.
Read the articleParents 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.
Read the articleIn 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.
Read the articleWhat ADU potential means on both sides of the transaction.
The five records that decide ADU potential, what never goes in listing remarks, how to value a unit with no comps, the appraiser's and inspector's versions of proficiency, and the handoffs a proficient agent makes without being asked.
Read the articleADU 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.
Read the articleWhat sellers must substantiate before advertising ADU potential, and what buyers must verify before paying for it.
Read the articleA 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.
Read the articleMassachusetts needs 222,000 homes by 2035 and ADU rights are statewide law. Why speaking ADU is becoming core competence for agents and associations.
Read the articleNearly 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.
Read the articleThree 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 articleAccessibility, aging in place, solar, and smart home.
Why "ADA compliant" is the wrong phrase for a private home, incentives stated as of a date, a separate household's privacy, lot coverage, and the professional who says the family does not need the thing they came in to buy.
Read the articleMost autistic adults live with their parents, and state support lines run for years. The cliff state by state across New England, what a separate legal unit changes, and an honest look at cost.
Read the articleThree 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 articleEvery 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.
The Ecosystem connects you with the REALTORS®, lenders, attorneys, and trade professionals each of these guides eventually points to.
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