Harwich ADU Regulations
Current zoning bylaws, requirements, and permit process for Accessory Dwelling Units in Harwich, Massachusetts. Last updated: October 2025.
Please Note: This information is provided for general informational purposes only and should not be considered legal or professional advice. ADU regulations are subject to change, and individual circumstances may vary. We strongly recommend verifying all requirements, zoning bylaws, and permit procedures directly with the Town of Harwich Building Department or Planning Board before beginning any planning or construction activities. Town officials can provide the most current regulations and guidance specific to your property and project.
Bullet Point Summary
- Maximum Size: 1,000 sq ft gross floor area or 1/2 net floor area of primary home or 900 sq ft, whichever is less
- Owner Occupancy Required: Previously required same owner for ADU and primary dwelling (conflicts with state law)
- Number of ADUs Permitted: One per primary dwelling
- Attached vs. Detached: Both allowed with special permit
- Parking Requirements: At least one off-street parking space for ADU
- Design Requirements: Must maintain single-family appearance; exterior must match character of existing home with matching materials, colors, window styles and roof design; max 2 bedrooms
- Septic/Title 5 Requirements: Must meet applicable zoning and sewer/septic regulations
- Rental Restrictions: Previously only one unit could be rented at a time, minimum 6-month rental period (may conflict with state law)
- Special Incentives: None identified
- Application Process: Previously required special permit from Zoning Board of Appeals; town is updating bylaws for 2025
Additional Information
For the most up-to-date and complete regulations, please contact the Harwich Building Department or visit the town's official website.
Our ADU specialists can help you navigate Harwich's specific requirements and design an ADU that meets all local regulations while maximizing your property's potential.