Accessory dwelling unit permit cost — Boston, MA

Looking for accessory dwelling unit permit cost in Boston, MA? Call AccessoryDwellingUnit Pros for a contact a provider — no obligation. Licensed adu builders serve Boston and the surrounding area, and you'll get straight answers on timing and what affects the price.

Last updated: September 24, 2026

What affects the price

Building an ADU is a custom project, so costs vary based on your specific choices. Site conditions are the biggest factor; if your land requires significant grading, utility extensions, or foundation work, those expenses add up quickly. Choosing high-end finishes, custom cabinetry, or complex roof lines will also push the budget higher compared to a standard design. Prefabricated units often offer predictable costs, while custom site-built structures allow for more flexibility but can be harder to estimate upfront. Exact pricing confirmed free on the call.

About this service

Permit fees are paid to your local municipality and fluctuate based on the specific city or county where your property is located. These costs cover plan reviews, impact fees, and safety inspections required to make your new space legal and compliant. Because every jurisdiction has a different fee structure, the final amount depends on your specific town’s regulations. We help you estimate these during the planning phase. Exact pricing confirmed free on the call.

Frequently asked in Boston

What are the disadvantages of ADUs in Boston?

How much does an ADU permit cost in Boston?

What are the rules for ADUs in Massachusetts?

Massachusetts has state-level ADU laws, but individual cities like Boston can have their own additional zoning ordinances. These often address things like lot size, setbacks, and owner occupancy requirements. A local pro can explain how Boston's rules apply to you. Call for advice.

Is an ADU allowed in Maryland?

While this service focuses on Boston, Maryland has its own regulations regarding ADUs. Cities and counties in Maryland have adopted various rules. If you're considering an ADU in Maryland, it's best to consult local building departments. We can help you in Boston.

Massachusetts, and Boston specifically, may have different incentive programs or financing options available for ADU construction. It's worth exploring local funding opportunities. Call for advice on what's available in Boston.

What are the rules for ADUs in California?

California has been a leader in ADU legislation, with statewide laws designed to streamline ADU development. These often include reduced parking requirements and streamlined permitting. However, specific local rules can still apply. We focus on Boston's regulations. Call us.

Also serving nearby: Quincy · Cambridge · Lynn · Newton · Brockton

All cities in Massachusetts →

More on this: HUD ADU resources — ADU policy and financing research.

Service area details

653,833residents

13,525per sq mile

8ZIP codes served

Serving all of Boston — population 653,833; about 13,525 residents per square mile across 48.3 sq mi. ZIP codes covered include 02108, 02109, 02110, 02111, 02112, 02113, 02114, 02115.

Neighborhoods served in Boston: Back Bay, South End, Beacon Hill, North End, Charlestown, Jamaica Plain — and every surrounding area.