Why Does ADU Permitting Take Months in One Massachusetts Town and a Week in the Next?

By Buz Artiano, BuildX | September 2026

Watch: ADUs, Septics, and Setbacks: The Real Constraints Nobody Talks About

You have an interest rate locked in but it has an expiration date, a parent who needs to move in before winter, and a builder that's wanting you to sign. Each part of the plan has a number but one. No one will tell you how long the city will take.

My name is Buz Artiano, and I am the founder of BuildX. We've built dozens of ADU projects across Massachusetts, mostly around the South Shore and Plymouth County areas. We are the only team you need: we do the design, permitting, and construction. So we see every phase of a project from the first site visit up until you move in. We evaluate septic constraints, zoning issues, utility connections and the requirements for a permit from the city. Massachusetts allows one accessory dwelling unit by right in single family zoning areas, although municipal building code, health code, and dimensional requirements still apply to every project. You can review the state requirements at mass.gov. Since we do everything under one roof, the permit time isn't just an abstraction to us. It's an important piece of our schedule.

Our position is simple. The time involved in getting a permit is the one thing that's discussed the least in an ADU budget and it's the one most likely to break a family's schedule, because it's the one major thing a builder doesn't control. And there can be time differences between two towns that are only twenty minutes apart.

How Wide Is the Permitting Gap Between Massachusetts Towns?

It's wide enough to change your whole project schedule. In one South Shore town an ADU approval takes about a week. Twenty minutes down the road the same approval takes months. It's the same state law, same by-right status, and same set of plans.

Greg Morse of Morse Engineering in Scituate came on our podcast with six ADUs in the permit stage in Scituate, Marshfield, Hanover, and Norwell. When we asked him what the differences were from his point of view, he said: "you can be talking months in Scituate, maybe a week in Hanover, and somewhere in between in Marshfield."

Those figures are one engineer's caseload at a certain time, and not a written city service standard. No Massachusetts town will commit to a time for an ADU approval, and none of the towns below are being called difficult. They're named because that's where the work is being done and because they are close enough together that a homeowner in one area thinks the next town's process will be the same.

The point isn't to shop for a town, since you already own the property. The point is that the middle column is the one thing that a builder can't control and it needs to be in your plan before you sign.

Why Do Some Towns Move Slowly on a Law That Removed Their Discretion?

Because the law took something away from them. Greg's thought on this match what these towns have been doing: "a lot of towns, especially the ones that already had allowed ADUs, maybe by a special permit, they don't want to give up the power that they had with a special permit."

A special permit is a discretionary approval: a local board votes on whether to allow the project at all. A town with no previous ADUs had no control to lose and now treats an ADU filing like a building permit. A town that gave ADUs approval through a special permit for years had a board, a hearing, and a vote, and that board is the slowest to let go. The towns that were most lenient before the law are often the slowest under it. That catches homeowners off guard.

The legality itself isn't in question. Massachusetts allows one accessory dwelling unit by right on single-family lots under the Affordable Homes Act, and a town can't require a special permit for it. The current requirements are published at mass.gov.

The state hasn't left the enforcement of that to chance. We've a memo from a town listing the ADU bylaw language the Attorney General's office told it to remove, crossed out line by line. We're not naming the town, and one memo isn't a pattern. But what it tells you is that the bylaw posted on your town's website isn't guaranteed to be the one that determines your filing.

If ADUs Are Allowed By Right, How Can a Town Still Take Months?

By right takes away the vote but it doesn't mean you won't have to wait in line. A by-right ADU still has to have a building permit, and depending on the property it might have to pass the Board of Health and the conservation commission. Neither of those boards lost power under the ADU law. In our experience, that is where the months can drag on.

We don't put a permit timeline in a client's schedule until we know which boards we have to deal with in that specific town. The building department is the by-right part and it can go slowly after that. The other boards work with meeting calendars. A board that meets once a month, and won't put a project on its agenda without a filing, establishes a limitation before anyone has seen your plan. If you miss the cutoff by a day, then you have to wait another full month. If someone requests revision then you will also have to wait. That's where the months come from. It isn't a vote against you, it's the calendar.

Who Speaks for You at the Town Hall Hearing?

Not you. When a project goes in front of a board, those sessions are public hearings at Town Hall, and all neighbors whose property adjoins yours are notified. The notice begins the conversation with the people next door, and it's better to have it before they get the notice.

The design and engineering team will do the presentation. Greg described his firm's practice the same way we do ours: they attend and they present the project. You're welcome to attend, and there are hearings where a homeowner talking for a few minutes about a parent moving in changes the tone of the meeting. The technical defense of the plan isn't your job. Ask who will present the plan before you sign, because if the answer is that you do, that's a schedule risk and a stress that you didn't consider.

What Should You Ask Your Town Before You Sign Anything?

Four questions, and one call to the building department answers most of them.

• Ask if the town allowed ADUs by special permit before the state law, and if the bylaws have been rewritten since then.
• Ask which other boards besides the building department have to sign off on an ADU at your address.
• Ask how often each of those boards meets and when the cutoff is for filing so you can get on the agenda.
• Ask whether any of the town's ADU bylaw language has been revised or eliminated by Attorney General review.

The first question tells you what kind of timeline you are looking at. The second and third give you the numbers: count the boards, count the meeting cycles, then add an extra cycle for revisions. The fourth tells you whether the rules you're seeing are the rules you will have to go by.

Then give the answers to whoever is quoting you the job. A builder who adjusts the schedule after reading them has filed for permits in your town before. One who tells you it won't matter, has not.

Build the Permitting Window Into Your Loan and Your Schedule

The time it takes to get permits isn't a construction problem. It's a financing and logistics issue that begins before construction starts. The move-in date you promised a parent, the expiration on a certain interest rate, the month you told a tenant, is all tied to a date the town controls and nobody has asked the town about.

You need to deal with it in a way that protects you. Figure out the number of boards and the meeting cycles first. Then change that into a permit timeline that is on the long end rather than an average. Take that information to your lender and to whoever is waiting for the ADU. A timeline that turns out shorter costs you nothing. Basing your timeline on the next town over can cost you the schedule and your credibility. When design, permitting, and construction are handled by one company, the permitting time is that company's problem to deal with. If it's divided between three companies, the time between approval and building is nobody's responsibility and that means it's yours.

There Are Projects We Tell Families to Delay

You'd expect a builder to tell you the permit process will go fine, because the builder who says otherwise might lose the project to the builder who doesn't. We're not going to tell you that.

If your town is on the slow side and your family needs the ADU occupied on a certain date, the date is the problem, not the ADU. There are times where the right move is to start the permit process at once and wait on the construction contract until approvals have been given. That's a slower way to do it and a smaller job for us. It also keeps a family out of living in a rental while the board goes through its agenda.

So treat these numbers the way we do. One engineer's projects in four different towns is real data from real files, and it's not a city standard. Your town could be on either side of it. The only number that will govern your project is the one your own boards give you.

Find Out Which Town You Are Actually In

The distance between a week and months isn't something you can negotiate. It's something you measure before the contract is signed, while the schedule can be changed. Every family we've built an ADU for on the South Shore has had a permitting window. The ones who found out early built around it.

The measurement just takes one call to your building department and one look at your town's current bylaw. Or we do it with you.