Can you build an ADU in Cohasset, MA?
The provided materials do not include Cohasset’s current accessory dwelling unit use provisions or supplemental standards. Dimensional rules alone are not enough to assess feasibility.
Confidence: low · Last researched August 2026
Dimensional standards in Cohasset, MA
| R-A — minimum lot area | 18,000 square feet |
| R-A — front setback | 20 feet |
| R-A — side setback | 15 feet |
| R-A — rear setback | 15 feet |
| R-B — minimum lot area | 35,000 square feet |
| R-B — front setback | 30 feet |
| R-B — side setback | 20 feet |
| R-B — rear setback | 20 feet |
| R-C — minimum lot area | 60,000 square feet |
| R-C — front setback | 30 feet |
| R-C — side setback | 20 feet |
| R-C — rear setback | 30 feet |
| HAR — front setback | 15 feet |
| HAR — side setback | 10 feet |
| HAR — rear setback | 15 feet |
| VIL — minimum lot area | 5,000 square feet |
| VIL — front setback | 15 feet |
| VIL — side setback | 10 feet |
| VIL — rear setback | 15 feet |
| 3A-C — minimum lot area | 10,000 square feet |
| 3A-C — front setback | 50 feet |
| 3A-C — side setback | 20 feet |
| 3A-C — rear setback | 20 feet |
| OS — front setback | 30 feet |
| OS — side setback | 20 feet |
| OS — rear setback | 30 feet |
| All districts — lot area calculation rule | May not include any land within the limits of an abutting street or private way, or any portion of the lot below mean high water |
| All districts — front setback measurement rule on narrow rights-of-way | Where a street has a right-of-way width of less than 40 feet, the setback distance shall include an additional 20 feet and be measured from the center line of the street |
Related questions
What are the setback requirements in Cohasset, MA?
Setbacks vary by district. Examples — R-A: 20 feet; R-A: 15 feet; R-A: 15 feet; R-B: 30 feet. Always confirm the exact yard requirements for your district with Cohasset, MA.
What is the minimum lot size in Cohasset, MA?
Minimum lot size depends on the zoning district — R-A: 18,000 square feet; R-A: 50 feet; R-A: 100 feet; R-B: 35,000 square feet.
How tall can buildings be in Cohasset, MA?
Height limits are set per district — R-A: 35 feet; R-A: 25 feet; R-B: 35 feet; R-B: 25 feet.
Full investor analysis
You've seen the general rule. The full Cohasset, MA report shows which districts allow ADUs by-right vs. by special permit, the approval path and timeline, and the overlay/flood constraints that quietly kill ADU projects here. First town report is free.
Get the full Cohasset, MA report free →More about Cohasset, MA zoning
- Can you build a duplex in Cohasset, MA?→
- Are short-term rentals allowed in Cohasset, MA?→
- Is mixed-use development allowed in Cohasset, MA?→
- What are the setback requirements in Cohasset, MA?→
This summary is AI-generated from public municipal sources and is not legal, engineering, or land-use advice. Always verify zoning with Cohasset, MA officials before making decisions.
More Massachusetts zoning reports →