Accessory Dwelling Units (ADUs) in Massachusetts: What Homeowners Need to Know

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Accessory Dwelling Units, commonly known as ADUs, are becoming one of the most popular ways for homeowners in Massachusetts to add space, increase property value, and create additional income.

Whether you’re thinking about building an in-law apartment, converting a garage, or adding a backyard unit, understanding the process is key.

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What Is an ADU?

An ADU (Accessory Dwelling Unit) is a secondary housing unit located on the same lot as a single-family home. It can be:

• A detached unit (like a small backyard home)

• An attached addition to the main house

• A converted space such as a basement, attic, or garage

ADUs are fully functional living spaces, meaning they typically include a kitchen, bathroom, and sleeping area.

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Why Build an ADU in Massachusetts?

Homeowners across Massachusetts are turning to ADUs for several reasons:

• Rental income – Generate monthly cash flow

• Family housing – Perfect for in-laws or adult children

• Increase property value – Strong return on investment

• Flexible living space – Office, guest suite, or rental

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Zoning and Regulations

ADU regulations vary by city and town in Massachusetts, so it’s important to check your local zoning bylaws.

Here are a few key things to look for:

• Lot size requirements

• Setbacks and placement rules

• Parking requirements

• Owner-occupancy rules (in some towns)

• Size limitations

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Do You Need a Permit?

Yes — building an ADU requires permits.

Typical permit process:

1. Visit your local town or city website

2. Check if the application is online or in person

3. Submit plans and required documents

4. Pay permit fees

What you’ll need:

• Design plans (sometimes stamped by an architect)

• Site plan

• Signed contract

• Licensed contractor with insurance

Important:

If you are adding or upgrading plumbing or electrical, those trades must pull their own permits.

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Costs to Build an ADU in Massachusetts

• Conversions: $80,000 – $150,000

• Additions: $150,000 – $300,000

• New detached units: $300,000 – $400,000+

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How Maize Restoration and Remodeling Can Help

Building an ADU can feel overwhelming, especially with zoning rules, permits, and design decisions. That’s where Maize Restoration and Remodeling comes in.

We are a design-build firm, which means we handle your entire project from start to finish:

• Initial consultation to understand your goals

• Full design and layout planning (virtual or in-person)

• Permit guidance and documentation

• Construction from foundation to finishes

• Coordination with plumbers and electricians

Our goal is to make the process simple, organized, and stress-free, while delivering a space that is both functional and beautifully designed.

We also help you:

• Maximize your layout for rental or family use

• Stay within budget

• Increase your property value

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Can You Build an ADU on a Multi-Family Property?

This depends on your local zoning. In many towns, ADUs are mainly allowed on single-family homes, but some areas are becoming more flexible.

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Final Thoughts

ADUs are one of the smartest ways to expand your home’s potential in Massachusetts. With proper planning and the right team, you can create a space that adds long-term value and flexibility.

If you’re considering building an ADU, working with an experienced design-build company like Maize Restoration and Remodeling can make all the difference.

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