As housing needs shift across New England—whether due to aging parents, adult children moving home, or a desire to generate rental income—Accessory Dwelling Units (ADUs) have emerged as a smart, flexible solution. They allow homeowners to expand how they live on their land—often with minimal new footprint and long-term payoff in comfort, care, or cash flow.
But what exactly is allowed? And where?
While regulations vary from state to state (and often town to town), recent legislation—especially in Maine—has opened new doors for homeowners across the region. Here’s what you need to know.
What’s an ADU, and Why Are They a Big Deal?
An Accessory Dwelling Unit (ADU) is a smaller, secondary home located on the same lot as a primary residence. It can be attached (like a finished basement or in-law suite), detached (like a small backyard cottage), or integrated within the main structure (such as a converted attic).
ADUs can serve as housing for family, guests, caregivers, or renters—and are gaining traction for their ability to support multigenerational living, aging in place, and more affordable housing options.
Thanks to LD 2003, Maine now requires municipalities to allow at least one ADU per single-family lot in areas where housing is permitted. As of July 1, 2023, homeowners can build:
Local governments can regulate size, setbacks, and design standards, but the right to build an ADU is protected statewide. This opens the door for many Mainers who were previously blocked by local zoning restrictions.
BrightBuilt Insight: This change has created a surge of interest in high-performance, prefab ADUs—especially in municipalities that are still adjusting to the new law.
Massachusetts has made strides, especially with Section 3A of the MBTA Communities Act, which requires 177 municipalities to create zoning that allows for “as-of-right” multi-family housing. While not specific to ADUs, it’s helping expand options.
Currently:
Tip: If you’re in Massachusetts and considering an ADU, it’s important to check your local zoning or work with a team (like ours) that understands the process.
In 2017, New Hampshire passed RSA 674:71–73, which requires all municipalities to allow one ADU per single-family home.
Key highlights:
BrightBuilt Insight: Many towns have embraced ADUs, but some continue to regulate them in restrictive ways. Check local ordinances—or bring us into the conversation early.
Vermont allows ADUs by right in many areas, thanks to 24 VSA §4412. Highlights include:
Vermont’s zoning can vary widely across towns, but the state has built-in support for homeowners pursuing small-scale, sustainable housing.
In 2021, Connecticut passed Public Act 21-29, which requires towns to allow ADUs by right—but with a twist: municipalities can opt out.
Currently:
If you’re in Connecticut, it’s best to start with your town’s planning department—or let us help you navigate it.
So, What’s the Bottom Line for Homeowners?
Across New England, the regulatory climate for ADUs is warming. While state laws differ, the momentum is clear: communities are moving toward more flexible housing options, and homeowners have more power than ever to shape the way they live.
And that’s where BrightBuilt Home can help.
With modular, high-performance ADU designs that are beautiful, energy-efficient, and code-smart, we help you bring your ADU vision to life—without the guesswork. From navigating local zoning to collaborating with your builder, we provide the experience, clarity, and design expertise to get you from “maybe we could” to “we did.”
Thinking About an ADU? Let’s Talk.
Whether you’re in Maine, Massachusetts, New England or anywhere else, we’re happy to help you explore what’s possible on your property—and how to make the process simple, sustainable, and worth it.
BrightBuilt Home
Thoughtfully designed. Sustainably minded. Clearly guided.
