ADU Parking Requirements in Cambridge, MA
ADU parking rules in Cambridge, Massachusetts. Required parking spaces, transit exemptions, and how to qualify for reduced parking.
ADU Regulations in Cambridge
Cambridge follows the Massachusetts state baseline under the Affordable Homes Act. This means all Massachusetts state-level ADU rights apply — including by-right approval, no owner occupancy requirement, and standardized size limits. Cambridge may also have additional local regulations that supplement the state baseline.
Transit Parking Exemption in Cambridge
Cambridge has transit stations, which means properties within 0.5 miles qualify for a complete parking exemption. This exemption applies to subway, commuter rail, bus rapid transit, light rail, and ferry terminal stations. Use our address checker to see if your property qualifies.
How the Transit Exemption Works
The transit parking exemption in Cambridge is measured as a straight-line distance from your property to the nearest transit station entrance. If you're within 0.5 miles, your ADU has zero parking requirements — this right is guaranteed by the Affordable Homes Act. This can free up significant lot area for the ADU itself.
Cambridge ADU Rules at a Glance
Max Size
900 sq ft
% of Home
50%
Max Height
25 ft
Max Stories
2
Front Setback
10 ft
Side Setback
5 ft
Rear Setback
5 ft
Parking
None required
Approval
BY RIGHT
Owner Occupancy
Not required
Rental Allowed
Yes
Short-Term Rental
Not allowed
Cambridge Building Department
Cambridge Inspectional Services
831 Massachusetts Ave # 1, Cambridge, MA 02139, USA
Phone: (617) 349-6100
Frequently Asked Questions
Are there parking requirements for ADUs in Cambridge?
Cambridge normally requires 0 parking space(s) per ADU. However, if your property is within 0.5 miles of a transit station, you're exempt from all parking requirements. Cambridge has transit stations — check your specific address to see if you qualify for the exemption.
How do I know if I qualify for a parking exemption in Cambridge?
Use our address checker to see if your property is within 0.5 miles of a transit station in Cambridge. We calculate the distance from your exact address to the nearest station. If you're within the radius, you have zero parking requirements for your ADU.
Can I use existing driveway parking for my ADU in Cambridge?
In most cases, existing driveway or garage spaces can count toward Cambridge's parking requirement, as long as the spaces meet dimensional standards (typically 9 ft wide by 18 ft deep). Check with Cambridge's building department for specific requirements on parking dimensions and configuration.
Which transit stations qualify for parking exemptions in Cambridge?
All transit stations in Cambridge qualify for the parking exemption. Properties within 0.5 miles of any station — including subway, commuter rail, bus rapid transit, and ferry terminals — are exempt from ADU parking requirements under the Affordable Homes Act.
Does tandem parking count for ADU requirements in Cambridge?
Tandem parking (cars parked one behind another in a driveway) may count toward Cambridge's ADU parking requirement, depending on local interpretation. This is a common question — confirm with Cambridge's building inspector before relying on tandem spaces.
What happens if I can't provide ADU parking in Cambridge?
If your property is near a transit station in Cambridge, you may be fully exempt from parking requirements. If you can't meet the parking requirement, options include applying for a variance, exploring shared parking arrangements, or choosing an ADU type (like a conversion) that may have different parking standards.
Where can I find all ADU regulations for Cambridge?
Visit our complete ADU rules page for Cambridge, MA for a full overview of zoning, permits, size limits, setbacks, parking, and costs. We cover all Massachusetts municipalities with data sourced from local ordinances and state law.
Check Your Address
See exactly what ADU rules apply to your specific property in Cambridge.