A practical guide for Massachusetts homeowners deciding whether to build
Since the Affordable Homes Act made accessory dwelling units (ADUs) buildable by right across most of Massachusetts, the question homeowners ask us has shifted from "am I allowed to build one" to "will one work on my lot."
Short answer: an ADU feasibility study in Massachusetts is a professional early-stage assessment of whether your property can support an accessory dwelling unit, covering site conditions, zoning, utilities, preliminary design, and a high-level budget. Under the state's ADU Incentive Program, launched July 21, 2026, listed providers charge no more than $500, and some charge nothing out of pocket.
It is not a set of plans and not a permit. It is the step that tells you whether the rest is worth starting.
Key Takeaways
- The Massachusetts ADU Incentive Program, run by the Massachusetts Housing Partnership (MHP), caps feasibility study fees at $500 for providers on its directory.
- A study does not include architectural designs, engineering plans, permit applications, or any guarantee that an ADU is constructable. Those are a later, separate step.
- ADUs under 900 sq ft (or 50% of the principal dwelling's gross floor area, whichever is smaller) are by right statewide, but Boston runs its own ordinance.
- Receiving a study does not obligate you to build, or to hire the provider who wrote it.
What an ADU feasibility study in Massachusetts actually includes
MHP does not prescribe a template, so formats vary. But the program defines five things a study should address:
- Your property's conditions and constraints. Lot shape, slope, existing structures, and how equipment would reach the build area.
- Local zoning and permitting. Setbacks, height, lot coverage, and any town rules layered on the state law.
- Utility needs. Water, sewer, and energy, including whether your electrical service can carry a second dwelling.
- Preliminary design considerations. What size and configuration the lot realistically supports.
- High-level cost and budget estimates. Enough to know whether it fits your finances.
Theory and site conditions diverge here. A 750 sq ft unit that complies on paper can still fail on access, grade, or a septic system that cannot take another bedroom. Our guide on whether you can build an ADU on your property goes deeper.
How the MHP ADU Incentive Program works
The Healey-Driscoll administration launched phase one of the ADU Incentive Program on July 21, 2026. MHP publishes a directory of providers chosen by competitive RFQ, pays each $500 per completed study, and those providers agreed not to charge homeowners more than $500.
Before you pick one:
- Any Massachusetts property where residential use is allowed may receive one study under the program.
- You work with the provider directly. MHP does not endorse anyone on the list, and each provider's fee is shown so you can compare before you commit.
MHP executive director Rachel Heller described a study as giving a family "an objective, professional assessment of what is possible on their property," according to the state's launch announcement. Inclusion on the list means a provider met minimum qualifications, not that they fit your town or your project.
Horizon ADU has been selected as a qualified provider of feasibility studies through the program. We would still tell you to read the directory first: the right provider is the one who knows your town and your kind of lot.
What an ADU feasibility study costs in Massachusetts
The $500 cap applies only to studies performed through the program. Outside it, pricing is set by the provider.
Step one is the only cost you take on to get an answer.
| Feasibility option | Cost |
|---|---|
| MHP program study, through a listed provider | Up to $500, and $0 out of pocket with some providers |
| Horizon ADU feasibility report | $200 |
Step two comes later, and only if you decide to build. You do not pay for any of it at the feasibility stage, and a study does not commit you to it.
| Item | Typical cost | When it applies |
|---|---|---|
| Survey / plot plan | $3,000 - $5,000 | Once you proceed |
| Architectural design | $3,000 - $8,000 | If you move ahead |
| Civil engineering | $2,000 - $4,000 | Only if the town requires it |
The reason to show both is scale. Against a build that runs $100,000 - $250,000 for a basement or garage conversion, $150,000 - $325,000 for an attached unit, and $200,000 - $360,000 for a detached cottage, feasibility is the cheapest decision point in the project, and the only one where a "no" saves you real money. Our ADU cost breakdown and hidden ADU costs rundown cover those ranges.
Can you get a free ADU feasibility study in Massachusetts?
In some cases, yes. Because the program pays providers directly, some on the MHP directory list a $0 out-of-pocket fee while others charge up to the $500 ceiling. Check the directory before assuming a study will cost you anything. To see where your own property stands, use our ADU Planner: enter your address, see what your lot may support, and we will contact you about ordering a $200 feasibility report.
What a feasibility study will not tell you
The limits matter as much as the contents. A study excludes architectural designs, engineering plans, construction documents, and permit applications, and does not guarantee an ADU is constructable, approved, permitted, or financed.
It also does not replace your town's zoning. Statewide ADU rules sit at 760 CMR 71.00, with construction under the Massachusetts State Building Code (780 CMR), but which framework a study is read against depends on where you live. Boston is excluded from the statewide by-right law and applies its own ordinance, including on owner-occupancy and parking. Our regulations hub and Boston-specific rules page lay out the difference.
What happens after the study
If the answer is yes, the sequence is predictable:
- Architectural design and survey: one to two months.
- Permitting: one to two months.
- Construction: three to four months.
Our guide to how long an ADU takes to build covers what stretches those windows. Nothing in that sequence starts, or gets billed, until you say so.
If the answer is no, you spent a few hundred dollars instead of several thousand on plans for a building that was never going to fit. That is a good outcome, even though it does not feel like one.
Frequently Asked Questions
How much does an ADU feasibility study cost in Massachusetts?
No more than $500 through the state's ADU Incentive Program. Providers on the MHP directory agreed to that ceiling in exchange for a $500 payment from the program. Outside the program, feasibility pricing varies by provider.
Can I get a free ADU feasibility study in Massachusetts?
Sometimes, yes. Some providers on the MHP directory list a $0 out-of-pocket fee because the program payment covers their work. Each provider's fee is listed on the directory.
What is included in an ADU feasibility study?
Five things: site conditions and constraints, local zoning and permitting, utility needs, preliminary design considerations, and high-level cost estimates. Format varies by provider, since MHP does not require a standard template.
Is a feasibility study the same as architectural plans?
No. A feasibility study explicitly excludes architectural designs, engineering plans, construction documents, and permit applications. Design work is a separate, later step, typically $3,000 - $8,000 in Massachusetts, and only if you choose to move forward.
Do I have to build an ADU after getting a feasibility study?
No. Receiving a study does not obligate you to build, and it does not obligate you to hire the provider who performed it for any further work.
Does the program work the same way in Boston?
The program does, but the zoning behind it does not. Boston is excluded from the statewide by-right ADU law and applies its own ordinance, so a Boston study must be read against city rules, not the state framework.
Final thoughts
A feasibility study is the least expensive honest answer you can buy about your own property, and the state has made it cheap enough to be worth doing.
The best ADU projects begin with a clear read of the lot, not an assumption about it.
If you are still researching, start with the ADU Planner: enter your address and see whether your property qualifies. We will follow up about ordering our $200 feasibility report if you want our read on the lot. When you are ready to talk through what it would take to build, get in touch with us directly.
About Horizon ADU
Horizon ADU is a Massachusetts design-and-build company, based in Boston and serving the entire state, specializing exclusively in stick-built, on-site ADUs, detached and attached. We do not build modular or factory-built ADUs. We analyze ADU regulations town by town across Massachusetts, and we are a qualified provider of feasibility studies through the MHP ADU Incentive Program. We hold an unrestricted construction supervisor's license and a home improvement contractor license, and we are fully insured.
Phone: 774-222-0127 · 77 King St, Boston, MA 02122