New Massachusetts Laws Regarding Accessory Dwelling Units (ADUs): Building a Guest House or In-Law Apartment Now Easier

In recent years, Massachusetts has faced growing challenges in its housing market, with increasing home prices and a lack of affordable housing options for residents. To address this growing crisis, the state has implemented a series of legislative changes aimed at expanding housing opportunities—one of the most promising being the new laws that make it easier for homeowners to build Accessory Dwelling Units (ADUs).

ADUs, which include in-law apartments, freestanding guest cottages, and finished garages, are secondary residential units located on the same lot as a primary single-family home. The idea behind these units is to provide more housing options within existing neighborhoods, potentially reducing the need for new, large-scale housing developments while also improving the affordability of housing. The recent legislative updates are designed to streamline the process for homeowners to create ADUs, thus promoting more efficient use of space, encouraging multi-generational living, and contributing to the state’s overall goal of easing the housing crisis.

For clients of our Cape Cod-based architecture firm, the implications of the change in regulations may facilitate long-held wishes to build a guest house that would allow their entire family to enjoy spending summers together. Extended visits from friends would also be much more comfortable.

Understanding Accessory Dwelling Units (ADUs)

Before diving into the specifics of the new Massachusetts laws, it’s essential to understand what ADUs are and why they matter. These small, secondary housing units can take a variety of forms:

• In-Law Apartments: These are separate living spaces within a larger home. They often include a kitchen, bathroom, and bedroom, and are ideal for extended family members, such as aging parents or young adults returning home after college.
• Freestanding Guest Cottages: These are standalone buildings on a homeowner’s property that are designed for short- or long-term guests. They typically have all the necessary living amenities, like a kitchen and bathroom, but are separate from the primary house.
• Finished Garages: An existing garage or outbuilding can be converted into a fully functional living space. Many homeowners with large properties can repurpose underutilized garages into ADUs to provide more rental or living opportunities.

These units can be used for a variety of purposes, including providing rental income from long-term leases (short-term rentals are not allowed), housing for elderly relatives, or serving as guest accommodations. They present a unique opportunity to expand the housing supply without the need for large-scale development or disruptive changes to neighborhoods.

How New Massachusetts Laws Make ADUs More Accessible

Historically, building an ADU in Massachusetts was a cumbersome process. Zoning laws and municipal regulations were often restrictive, and many cities and towns had specific requirements about the size, design, and location of ADUs. However, a series of new state laws passed in recent years has dramatically simplified the process. Here are the key aspects of these new laws:

1. Relaxed Zoning Restrictions

One of the primary challenges homeowners faced in the past was that zoning laws often prohibited or severely restricted the construction of ADUs. With the new changes, Massachusetts has made it easier for homeowners to build ADUs by relaxing these zoning restrictions. Some cities and towns in Massachusetts have implemented zoning reforms that:

• Allow ADUs by Right: In many cases, homeowners no longer need to seek special permits or variances to build an ADU. This “by-right” approval streamlines the permitting process and removes many bureaucratic barriers.
• Reduced Minimum Lot Size Requirements: The new laws reduce the minimum lot size required to build an ADU, making it easier for homeowners with smaller properties to build these units.

2. Simplified Approval Process

The approval process for building an ADU has also been simplified under the new laws. In many areas, homeowners can now bypass time-consuming public hearings or approval from zoning boards. Instead, they only need to submit their plans for review by local building departments. This can save considerable time and effort for homeowners seeking to add an ADU to their property.

Furthermore, municipalities are required to approve or deny ADU applications within a set time frame (typically 90 days). This ensures that the process is not dragged out unnecessarily and gives homeowners a more predictable timeline for when they can begin construction.

3. Incentivizing Affordable ADUs

In addition to making it easier for homeowners to build ADUs, the new laws provide incentives for homeowners to create affordable rental units. Massachusetts has introduced financial incentives, such as grants, tax breaks, and low-interest loans, to encourage homeowners to offer ADUs as affordable housing units. This is particularly important given the rising cost of living in the state, where many renters are struggling to find affordable housing.

• Affordable Rent Requirements: Homeowners who choose to rent their ADU at an affordable rate may be eligible for property tax reductions or grants to help with construction costs. For example, if a homeowner rents their ADU to someone earning 80% or less of the area median income, they may qualify for these incentives.
• Increased Funding for ADU Construction: The state has also made it easier for homeowners to access funding to help cover the costs of building or renovating an ADU. These funds may come from the state or federal programs, and in some cases, municipalities may offer their own local grants or subsidies.

Conclusion: A Step Toward a More Sustainable Housing Future

The recent legislative changes in Massachusetts that make it easier to build ADUs represent an important step in the right direction. By relaxing zoning restrictions, simplifying the approval process, and providing incentives for affordable units, the state is creating a more flexible, sustainable housing solution that can meet the needs of a growing population. ADUs can provide more rental options, support multi-generational living, and help increase housing density without the environmental and social challenges associated with larger developments.