ADU Regulations:
Medford
Regulations Snapshot
Rear and Side setbacks: 3 feet
Building Separation: 10 feet
Height: 35 feet
Stormwater management: Yes, depending on amount of impervious area
Sprinkler system: Yes, see below for details
Separate utilities required: No
Impact Fees: None listed

Building Constraints
Number of ADU’s allowed on a single family lot
One
Maximum square footage of an ADU (detached or attached)
The maximum floor area of an ADU shall not exceed 900 square feet, or 50% of the total gross floor area of the principal dwelling unit, whichever is smaller.
Maximum Height
35 feet (same as primary home)
Maximum lot coverage
Can't be more than 25% of rear yard ( all area behind the house)
Exterior appearance requirements
Congruent with primary house
Setbacks
Rear setback
3 feet
Side setback
3 feet
Front setback
Same as primary house
Distance between buildings
10 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
Typically two off-street parking spaces
Additional Requirements
Separate utilities required
No, they can connect to the primary house
Stormwater management required
Yes, the size of the system is linear with the amount of impervious area created by the ADU (this can add $15k – $20k to the project)
Site plan review required
No
Town impact fees
None listed
Fire safety requirements
Not needed if less than 50 feet from the sidewalk. If more than 50 feet then a 20′ wide access path is needed. If not, a sprinkler system is required.
Soils report required
No, the building department will inspect the hole prior to construction of the foundation
Civil plans required
Yes
Short term rental allowed
No
Possible overlay districts
Historic, wetland, conservation land
ADUs on multifamily lots
Allowed
