Working With Us
Hiring an ADU builder in Harwich
Lower Cape ADU is a licensed accessory dwelling unit builder serving Harwich and the seven other Lower Cape towns. Our office is in North Eastham, at Unit #7, 4250 State Highway, a short run down Route 6 to Harwich. Harwich lots tend to give us more room to work with than the Outer Cape offers.
Harwich generally offers more lot area and more straightforward siting than the Outer Cape, and parts of town have sewer access. That often makes a detached cottage the strongest option here — but it depends on the parcel.
We handle Harwich ADU projects end to end — site assessment, design, permitting, and construction supervision — so you are working with one accountable party from the first conversation through to occupancy, rather than coordinating a designer, an expediter, and a contractor yourself.
- Vern Hatt, owner
- MA Construction Supervisor License #CS62739
- MA Home Improvement Contractor License #177590
- Office in North Eastham
What an Harwich ADU project looks like
-
Free consultation
We sit down with you — no charge, no obligation — and talk about what you are actually trying to solve on your Harwich property: rental income, room for family, a place to downsize into, or staying put as you age.
-
Property assessment
We walk the property and look at the things that decide the project: lot area, setbacks, septic or sewer, grade, access, and what the existing house can support.
-
Legal and physical limits
We establish what Harwich and the Massachusetts Affordable Homes Act actually allow on your parcel, so the design starts from a real envelope rather than a hopeful one.
-
Preliminary design and estimate
We produce a preliminary design and a good-faith estimate as part of the bidding process, so you can see the project and its cost before committing to anything.
-
Permitting
We prepare and submit the permit package and represent the project before the Harwich Building Department, the Harwich Board of Health on septic or sewer connection questions, and where a project calls for it, the Conservation Commission as required.
-
Construction supervision
We supervise construction through to occupancy, as a licensed Massachusetts Construction Supervisor working on your Harwich property.
What We Build
Types of ADUs we build in Harwich
Which of these fits depends on your lot, your septic or sewer situation, and what you are trying to accomplish. We work through that with you before recommending one.
Standalone Cottages in Harwich
A detached cottage on your own lot — the most flexible option when land and septic allow it.
Garage Conversions in Harwich
Converting an existing garage, or building above one, often on an already-approved footprint.
Basement Conversions in Harwich
A lower-level unit using space you already have, where ceiling height and egress work out.
Attic Conversions in Harwich
Overhead space turned into a compact unit without expanding the building footprint.
Modular & Prefab in Harwich
Factory-built units that shorten on-site construction time and tighten the schedule.
The Local Picture
Harwich offers space, harbors, and easy connection
Harwich spreads across the Cape's south side with three harbors — Saquatucket, Wychmere, and Allen — historic cranberry bogs, and the trailhead of the Cape Cod Rail Trail. It's a town of villages, from Harwich Port to West Harwich, with a strong year-round population and more available land than the towns at the Cape's tip. That extra room, combined with good road and trail connections, makes Harwich one of the most practical places on the Lower Cape to add an ADU.
Why an ADU Fits Here
Harwich character, Harwich opportunity
What makes Harwich Harwich—and how a well-designed accessory dwelling unit fits naturally into it.
Three Harbors
Saquatucket, Wychmere, and Allen Harbors give Harwich a deep maritime character and steady seasonal activity — and a year-round community that needs places to live.
Cranberry Bogs & Open Land
Harwich's bogs and comparatively larger lots mean many properties have genuine room for a tasteful detached cottage, often making an ADU more straightforward here than in denser towns.
Cape Cod Rail Trail
The Rail Trail begins in Harwich, linking the town to its neighbors by bike and foot. That connectivity makes a Harwich ADU attractive to year-round tenants who value getting around without a car.
Harwich Port Villages
Harwich's village centers, especially Harwich Port, offer walkable cores and a relaxed feel — a strong setting for an ADU serving family, rental, or downsizing needs.
The Rules, In Brief
Harwich ADU rules at a glance
How the statewide ADU law applies in Harwich — and what still gets decided locally.
By-Right, Statewide
Since February 2025, a first ADU is allowed by right in single-family zoning under the Affordable Homes Act, with no owner-occupancy requirement for that unit.
Size Limits
By-right units are capped at 900 square feet or 50% of the primary dwelling, whichever is smaller.
Septic & Watersheds
Harwich's many ponds and harbors mean Title 5 septic capacity and watershed protection can influence ADU bedroom counts and placement.
Local Dimensional Rules
Setbacks, height, and lot coverage remain town-set. Harwich has been reconciling its bylaw with state law, so confirming current local details is wise.
Local Knowledge
What to think about for a Harwich ADU
Of the eight Lower Cape towns, Harwich often gives homeowners the most flexibility. Larger lots and a town outside the National Seashore mean a detached cottage is frequently feasible without the land constraints that dominate the Outer Cape. The considerations that remain are mostly environmental — septic capacity and the watersheds feeding Harwich's many ponds and harbors can govern how many bedrooms a lot supports. For owners who want a clear, buildable path to rental income or a downsizing home, Harwich is one of the easier places to start. We begin with your lot's septic and setback picture and design from there.
Permitting an ADU in Harwich typically involves the Harwich Building Department, the Harwich Board of Health on septic or sewer connection questions, and where a project calls for it, the Conservation Commission. We prepare the package and represent the project through that process as part of every job.
Common Questions
Harwich ADU questions we get asked
Do I need a special permit to build an ADU in Harwich?
Under the Massachusetts Affordable Homes Act, a first accessory dwelling unit is allowed by right in single-family zoning, which means a special permit is generally not required for that first unit. You still need a building permit, and Harwich still applies its own setback, height, and lot coverage rules. Second units, oversized units, or properties in overlay districts may require additional local review. We confirm the current requirements with the town as part of every project.
How big can an ADU be in Harwich?
The by-right cap is 900 square feet or 50% of the primary dwelling’s floor area, whichever is smaller. On a modest Harwich home, the 50% figure is often the binding number rather than the 900 square feet — which is why we measure the existing house early instead of assuming.
Will septic or sewer limit an ADU on my Harwich property?
Harwich has been expanding municipal sewer in parts of town, including areas around Harwich Center and East Harwich, while other neighborhoods remain on private septic. Sewer access can simplify an ADU considerably, so confirming availability at your specific address is one of the first things we do.
How long does an ADU project take in Harwich?
Design and permitting typically run a few months, and construction depends on the type of unit and the season. Garage, basement, and attic conversions generally move faster than new detached construction. We give you a realistic schedule for your specific Harwich property at the consultation rather than a generic range.
Can I rent out an ADU in Harwich?
Long-term rental of an accessory dwelling unit is generally permitted. Short-term rental rules are set locally and vary meaningfully from town to town on the Lower Cape, so if short-term rental income is part of your plan, confirm current Harwich rules before you build. We raise this early because it can change which design makes sense.
Let's Talk
Thinking about an ADU in Harwich?
The first conversation is free. Tell us about your Harwich property and what you are trying to solve — rental income, family space, or downsizing in place — and we will walk you through whether it makes sense, with a preliminary design before any estimate.
Start with a Free ConsultationVern Hatt · Licensed Construction Supervisor #CS62739 · Home Improvement Contractor #177590