Holbrook · Norfolk County

Can you build an ADU in Holbrook?

Every other town on this list wrote something of its own after February 2025: a review step, a minimum size, a design test. Holbrook wrote nothing. We read the warrants for all three of its town meetings since the law took effect and none of them contains an accessory dwelling unit article, which leaves the state floor governing directly.

What the state guarantees you

Since 2 February 2025 this applies in every Massachusetts community. A town may be more generous than this. It may not be less.

Rule	What it means
Allowed by right	One ADU in single-family zoning districts, statewideNo special permit and no public hearing for a protected-use ADU
Maximum size	900 sq ft, or 50% of the principal dwelling, whichever is smallerA town may allow larger. It cannot allow smaller
Owner occupancy	A town cannot require itSo you may rent both units, or live in the ADU and rent out the house
Parking	One space at most, and none at all within half a mile of transitA town cannot ask for more than this
Short-term rental	The state leaves this to each townAll six towns documented here ban it, and two of them ban it for the main house too
In force since	2 February 2025Any conflicting local zoning became unenforceable that day

What Holbrook adds on top

Rule	In Holbrook
Local ADU bylaw	None adopted since the state law took effect on 2 February 2025
Meetings checked	Annual, 14 May 2025. Special, 19 November 2025. Special and Annual, 27 May 2026. No ADU article in any of the three warrants
What governs	760 CMR 71.00 and G.L. c.40A as amended by the Affordable Homes Act, applied directly
Where allowed	By right wherever single-family dwellings are allowed
Maximum size	Half the principal dwelling's gross floor area or 900 sq ft, whichever is smaller
Special permit	Not required for a protected use ADU
Public hearing	Not required for a protected use ADU
Owner occupancy	Cannot be required
Parking	One space at most, and none within half a mile of a transit station
Short-term rental	The state permits a town to prohibit it. Holbrook has adopted no ADU bylaw doing so, though any separate town rules on short-term letting would still apply
Still applies	Ordinary zoning. The statute makes an ADU subject to otherwise applicable dimensional and parking requirements, so Holbrook's existing setback, height and coverage rules for accessory structures govern the building itself

A town that legislated nothing is not the same as a town with no rules, and the distinction is worth holding onto. What Holbrook has not done is add an ADU-specific layer: no site plan review as in Rockland, no 400 sq ft floor or Board of Appeals step as in Whitman, no exterior judgement call as in Bridgewater. What still binds you is the ordinary zoning that binds any accessory structure, plus the building code and Title 5 where the lot is on septic. In practice that makes Holbrook the shortest route from idea to permit of the towns documented here, and the one where the state's own limits are the whole of the answer. Since a town can adopt a bylaw at any town meeting, check with the Building Department before you rely on this for a specific lot.

Questions people ask

Does Holbrook have its own ADU bylaw?

No. We read the warrants for Holbrook's three town meetings held since the state law took effect on 2 February 2025, being the May 2025 annual, the November 2025 special and the May 2026 special and annual, and none contains an accessory dwelling unit article. The state regulations govern directly.

Do I need a special permit for an ADU in Holbrook?

Not for a protected use ADU. With no local bylaw adding a review step, the state position applies: allowed by right in single-family zoning, with no special permit and no public hearing.

Does that mean there are no rules at all?

No. The statute makes an ADU subject to otherwise applicable dimensional and parking requirements, so Holbrook's ordinary zoning for accessory structures still governs setbacks, height and coverage, as do the building code and Title 5 on a septic lot.

Could Holbrook adopt an ADU bylaw later?

Yes. Any town meeting can take up a zoning article, and a town may add reasonable regulation so long as it does not go below the state floor. Check with the Building Department before relying on this for a specific property.