FAQ
ADU Basics
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An “Accessory Dwelling Unit” (ADU) is a self-contained living space on the same lot as a single-family home that has its own kitchen, bathroom, and entrance, yet it remains subordinate in size and design to the main home.
In Massachusetts, the law defines it under the Affordable Homes Act and requires it to be no larger than 900 sq ft or 50% of the main home’s floor area, whichever is smaller.
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Yes.
Under statewide law, every municipality must allow at least one ADU on a property with a lawfully existing single-family home in a single-family zone, without requiring a special permit or owner-occupancy.
That said, local towns can still impose “reasonable” regulations such as setbacks, height limits, Title V/septic compliance, and design review.
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For size, your ADU must not exceed 900 sq ft or ½ the size of the main living area (whichever is smaller).
On use, you may rent the ADU, live in it, or house relatives. Municipalities may not impose an owner-occupancy requirement or ban normal rentals.
Building & Permitting
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From design to move-in, most ADUs take 4–7 months to complete. The first 1–2 months cover design, site evaluation, and permit approvals, while the remaining time is dedicated to construction. Factors like winter conditions, zoning reviews, or custom design choices can extend timelines slightly.
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In most Massachusetts towns, ADUs are now allowed by-right, meaning you’ll typically only need standard building permits rather than a special permit or zoning variance. However, local building departments may still review your plans for compliance with septic, fire, and setback regulations before issuing final approval.
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Costs vary based on size, layout, and finishes, but most homeowners invest between $150,000 and $300,000 for a complete turnkey ADU.
Converting an existing basement or garage can cost less, while detached backyard cottages or custom additions may be higher.
The good news: many ADUs generate $1,500–$3,000 in monthly rental income, helping pay themselves off over time.
Financial Impact
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In Massachusetts, ADUs can bring in anywhere from $1,800 to $3,500 per month, depending on location and design.
Many homeowners find that their ADU can cover its own financing costs, and then some, within just a few years.
It’s one of the simplest, most dependable ways to turn unused space into steady, passive income.
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Homeowners have several easy options, including home equity loans, cash-out refinancing, or construction loans designed specifically for ADUs.
In most cases, your projected rental income can even help you qualify.
We can connect you with trusted local lenders who understand ADU financing and make the process smooth from start to finish.
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With typical rental rates, many ADUs pay for themselves within 5–7 years, sometimes sooner.
Once your initial costs are covered, that rental income becomes pure profit, month after month.
Whether it’s a detached cottage or a converted basement suite, an ADU is a turnkey path to financial freedom built right into your property.
Top Questions
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Absolutely . An ADU is one of the smartest home investments you can make.
Most homeowners see their property value increase by $100K–$250K while also generating $1,800–$3,500+ in monthly rental income.
Whether you use it for family or tenants, it’s a tangible asset that pays you every month while boosting your home’s long-term value.
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From design to move-in, most projects take 5–7 months. That includes permitting, construction, and final finishing.
Because ADUs are smaller and now allowed “by right” in Massachusetts, they move faster and with fewer headaches than traditional home additions.
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Everything. We handle design, permitting, financing connections, construction, and finishing touches, all under one roof.
Our goal is to make it effortless for you to go from idea to income without juggling multiple contractors or worrying about the details.
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Just about anything.
Many homeowners build ADUs for aging parents, college-aged kids, or visiting family.
Others turn them into work-from-home studios, guest cottages, or even creative spaces like gyms or art rooms.
It’s your property, your way to add comfort, privacy, and long-term value.
Rules & Regulations
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Yes.
Massachusetts law allows a complete, self-contained living space including a full kitchen, bathroom, and sleeping area, as long as it meets building and safety codes.
That means your ADU functions as a true second home on your property.
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In most Massachusetts towns, yes, as long as the total height stays within local zoning limits.
Garage conversions and above-garage ADUs are a smart way to maximize space without expanding your property’s footprint.
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Many Massachusetts towns no longer require owner occupancy, meaning you can rent out both the main home and the ADU if you choose.
This flexibility makes it easier than ever to generate passive income or prepare for future family use.
Glossary
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An ADU (Accessory Dwelling Unit) is a self-contained living space , with its own kitchen, bathroom, and entrance.
A addition simply adds square footage to your main home.
ADUs add independence, rental potential, and resale value, while additions just add space.
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A detached ADU stands alone in your backyard, like a small cottage or guest house.
An attached ADU shares a wall with your home or sits above a garage.
Both create privacy and flexibility, the best choice depends on your property layout and goals.
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“By right” means you’re legally allowed to build an ADU without special hearings or variances, as long as your design meets local standards.
In Massachusetts, this makes it simpler, faster, and smarter than ever to build an ADU and start earning from your property.