Key Requirements
Permit Type
By Right
Permit Authority
Building Inspector
Local Terminology
ADU
Max Size (sq ft)
900
Max Size (% of principal)
50%
Size Rule
Whichever is smaller
Attached Allowed
Yes
Detached Allowed
Yes
Internal Allowed
Yes
Parking Spaces Required
1
Transit Exemption
Yes
Short-Term Rental
Prohibited
Owner Occupancy Required
No
Design Review Required
Yes
Historic District Review
—
Energy Code
Stretch Code
HERS Rating Required
Yes
Max HERS Index (ADU)
52
Quick Summary
- Gloucester (a city, not a town) has an adopted ADU ordinance (Section 5.24) in its zoning code, with provisions for both attached and detached ADUs.
- ADUs are allowed by right with a building permit from the Building Inspector -- no special permit or public hearing required.
- Maximum size is 900 sq ft or 50% of principal dwelling, whichever is less, with a maximum of 2 bedrooms.
- Short-term rentals prohibited -- minimum 30-day rental/occupancy term; no boarding or lodging.
- Detached ADUs have tiered height limits: 20 feet (accessory building setbacks) or 24 feet (principal dwelling setbacks).
Requirements at a Glance
| Requirement | Rule |
|---|---|
| Permit type | By right (building permit from Building Inspector) |
| Max size | 900 sq ft or 50% of principal dwelling, whichever is less |
| Bedrooms | Maximum 2 bedrooms |
| Attached / Detached / Internal | All types allowed |
| Parking | 1 space; 0 within 0.5 miles of transit (state law) |
| Owner occupancy | Not required (state law preempts local provision) |
| Short-term rental | Prohibited (minimum 30-day rental term) |
| Separate sale | Prohibited |
| Detached height | 20 ft (accessory setbacks) or 24 ft (principal dwelling setbacks) |
| Permit authority | Building Inspector |
ADU Questions in Gloucester
Can I build an ADU in Gloucester, MA?
Yes. Accessory dwelling units are allowed by right in Gloucester, MA, meaning you do not need a special permit or a zoning variance as long as the unit meets the town's dimensional rules. You still need a building permit from the Building Inspector. Gloucester calls these "ADU."
How big can an ADU be in Gloucester, MA?
Gloucester limits an accessory dwelling unit to 900 square feet or 50% of the principal dwelling, whichever is smaller. State law protects ADUs up to 900 square feet on single-family lots, so a town cannot enforce a smaller cap on a protected-use ADU. The bylaw also caps the unit at 2 bedroom(s).
What types of ADU are allowed in Gloucester, MA?
Gloucester permits 3 forms of accessory dwelling unit: detached (a separate structure in the yard); attached (an addition to the house); internal (a conversion of existing space). Which one makes sense usually comes down to your lot, your septic or sewer situation, and whether you want the unit connected to the main house.
Does Gloucester, MA require extra parking for an ADU?
Gloucester's bylaw calls for 1 additional off-street parking space(s) for an ADU. Under state law, towns cannot require more than one space for a protected-use ADU, and no parking at all can be required within a half mile of transit.
Do I have to live on the property to rent out an ADU in Gloucester, MA?
No. Gloucester does not impose an owner-occupancy requirement, and state law bars towns from requiring it for protected-use ADUs. You can rent the unit without living on site.
What energy code applies to an ADU in Gloucester, MA?
Gloucester has adopted the Stretch Energy Code. That means a new ADU must hit a HERS rating of 52 or lower, which drives real decisions about insulation, air sealing, windows, and heating — typically an all-electric heat pump system. Budget for a HERS rater on the project from day one.
Can I use an ADU in Gloucester, MA as a short-term rental?
No. Gloucester prohibits using an accessory dwelling unit as a short-term rental; the minimum lease term is 30 days. The unit is intended for long-term housing. State law expressly allows towns to restrict short-term rental of ADUs, so this restriction does hold up.
Based on Gloucester’s bylaw as last verified 2026-02-25. Bylaws change at annual town meetings — confirm with the Building Inspector before you build.