ADU Regulations:
Weymouth
Regulations Snapshot
Rear and Side setbacks: side – 10 feet, rear – 20 feet
Building Separation: 10 feet
Height: 2 stories or 25 feet
Separate utilities required: No, can connect to existing
Stormwater management required: No
Specialized Stretch Energy Code: No
Impact Fees: $3,070 per bedroom for water/sewer mitigation and hookup
Building Constraints
Number of ADU’s allowed on a single family lot
Only one ADU is allowed per single-family lot, whether interior, detached, or attached
Maximum square footage of an ADU (detached or attached)
Up to 900 square feet or half the gross floor area of the primary dwelling, whichever is smaller
Maximum Height
2 stories or 25 feet and may not exceed the height of the primary structure, whichever is smaller
Maximum lot coverage
For lots exceeding 25,000 square feet a detached ADU of 900 sf or ½ the size of the primary structure is allowed. For lots less the 25,000 sf, the ADU is limited to 750 sf Lots less than 5,000 sf are ineligible for an ADU
Exterior appearance requirements
All ADUs requiring a building permit shall be required to have a design review as well as Site Plan Approval. Design reviews are only recommendations to ensure ADUs are constructed of similar material and in a complementary design to primary structures on site and on immediately adjacent lots.
Setbacks
Rear setback
Weymouth follows the dimensions of the underlying zoning. If in a single family zone the rear setback is 20 feet or ⅕ the depth of the lot, whichever is smaller
Side setback
Weymouth follows the dimensions of the underlying zoning. If in a single family zone, the side setbacks are 10 feet. If on a corner lot they are 18 feet
Front setback
The ADU must be in line with or behind the primary structure
Distance between buildings
10 feet
Height
2 stories or 25 feet
Parking
Parking requirement for an ADU
Each ADU requires one off-street parking space in addition to what is required for the primary dwelling. No parking space is required for an Accessory Dwelling Unit on a Lot if any portion of such Lot is located within a 0.5-mile radius of a Transit Station.
Where can the parking be located : Parking requirement for primary dwelling
2 off street parking spaces
Where can the parking be located
None
Additional Requirements
Separate utilities required
Utilities should connect to existing and not make new road cuts. Can do in the basement or in the yard between the house and street. Water would need a submeter for rental. Can get water sewer tie cards from the town which shows where water/sewer comes into building
Stormwater management required
Engineering report not required. It is recommended that downspouts run into a leaching pit but not required.
Site plan review required
Yes, a public hearing is held within 30 days of application receipt. A decision is made within 45 of the public hearing. Note that the purpose of the hearing is to shape the project, it cannot be rejected entirely if the by-right restrictions are met.
Town impact fees
$2,200 per additional bedroom for water/sewer mitigation fees, $770 per bedroom for sewer connection fees, $100 application fee
Soils report required
No, the building department will just inspect the hole prior to foundation build
Civil plans required
Yes
Short term rental allowed
No
Possible overlay districts
There is a History Mill District, a Watershed Protection District and a Groundwater Protection District which could affect ADU building requirements
ADUs on multifamily lots
Currently not allowed on multi family lots.