Attleboro · South Attleboro · Dodgeville · Hebronville

Attleboro’s ADU parking rule reaches further than the state’s does

Attleboro has a proper post-Act ADU ordinance — Sec. 17-4.5, with real standards and a 900-square-foot cap. One provision is drawn wider than the state rule allows: it measures your half-mile from a transit station or a public bus stop, and the state regulation does not use that second term.

Attleboro’s ordinance uses accessory dwelling unit. Homeowners in South Attleboro and Hebronville more often say in-law apartment, or backyard apartment for a detached cottage. Sec. 17-4.5 covers them all.

Drawn wider than the state rule · Worth questioning on your parcel

One additional parking space is required only if the lot lies more than half a mile from a transit station or public bus stop.

Sec. 17-4.5.2C(4), Attleboro Zoning Ordinance

Read literally that is more generous than the state rule where a bus stop is nearby — a bus stop inside the half mile means no space required at all. But 760 CMR 71.02 defines a Transit Station as a subway, commuter rail, ferry or bus station, not a bus stop, and the ordinance’s own wording is what the city will apply. Either way the ceiling is fixed: for a protected-use ADU a municipality may require no more than one additional space. If anyone asks for two in Attleboro, that is the number to push back on.

What the ordinance sets out

Size: 900 sq ft, or 50% of the principal dwelling’s gross floor area, whichever is less.Sec. 17-4.5.2C(1)
Parking: One space, subject to the half-mile test above — and capped at one by state law regardless.Sec. 17-4.5.2C(4); 760 CMR 71.03(2)(b)
Where it sits: Sec. 17-4.5 covers accessory structures and accessory dwelling units together; Sec. 17-4.5.2 carries the ADU general standards.Sec. 17-4.5; Sec. 17-4.5.2

Attleboro is a city, so check currency differently

There is no Attorney General review of city ordinances under G.L. c.40 §32 — the AG index is not the check here, the ordinance currency date is. The file we hold carries Sec. 17-4.5 and Sec. 17-4.5.2 with 23 hits on accessory dwelling language, so a post-Act provision is genuinely published. But the stamp on that file is a download date, not an adoption date. We confirm the currency date with the City Clerk before quoting any figure from it.

Measuring the 50%

The state definition at 760 CMR 71.02 governs the size of a protected-use ADU, and a local definition cannot shrink a state entitlement. We compute the half-GFA figure on the state definition and carry the local number alongside it, because a local official may well reach for the local one.

760 CMR 71.02; Attleboro’s own cap at Sec. 17-4.5.2C(1)

Both the ordinance and the state rule land on the smaller of 900 square feet or half your house, so the cap itself is not in dispute here — only how the half is measured. Work your number on the ADU size calculator.

Setbacks

The district setbacks that apply to your parcel are read off the adopted dimensional table for your specific district, and we do that on your address rather than print a number here that may not be yours. Attleboro’s dimensional table runs by district, and South Attleboro, Dodgeville and Hebronville sit in different ones. We read the row for your district against the ordinance rather than print a figure that may not be yours.

One thing to raise deliberately: 760 CMR 71.03(3)(b)(2) does not allow a town to impose dimensional standards on a protected-use ADU that are more restrictive than those for a principal dwelling. Where an accessory-structure row is stricter than the principal row, that is the provision to point at.

760 CMR 71.03(3)(b)(2)

Sewer, septic, and which one you are on

Much of Attleboro proper is on municipal sewer, and much of the outer city is not. On sewer, the wastewater question largely disappears and the budget question becomes the connection. On septic, Title 5 tests design flow across the whole property’s bedroom count, and whether your existing system carries the added bedroom is the number that decides the project.

310 CMR 15.000

Which of those two you are in is the first thing we establish. Planning ranges are in our cost guide.

We will tell you whether it works before you spend anything

Southcoast Building is an approved Feasibility Study Provider under the Massachusetts Housing Partnership ADU Incentive Program. A licensed builder walks your property, reads your parcel against the bylaw, checks the septic and the grading, and tells you whether an ADU works here and roughly what it would cost. Thirteen of our studies have been approved by MHP to date.

Request your free study

$0 to you under the MHP ADU Incentive Program · One study per property · Michael Bicho · (508) 269-2131

Where these figures come from

City of Attleboro Zoning Ordinance — Sec. 17-4.5 (accessory structures and accessory dwelling units) and Sec. 17-4.5.2 (ADU general standards), including C(1) size and C(4) parking. Held file searched in full 2 September 2026, 23 accessory-dwelling hits. Currency date to be confirmed with the City Clerk.
760 CMR 71.00 — §71.02 defines Transit Station as a subway, commuter rail, ferry or bus station; §71.03(2)(b) caps required parking at one additional space; §71.03(3)(b)(2) bars dimensional standards stricter than those for a principal dwelling.
Attleboro is a city, so its ordinances are not submitted for Attorney General review under G.L. c.40 §32 and no AG decision exists to check against.
310 CMR 15.000 (Title 5) for the design-flow and bedroom-count test.

Zoning changes, and a building inspector’s reading of it is the one that governs your permit. Nothing here is a determination about your property. It is what the adopted text and the Attorney General’s decisions say as of 8 September 2026.