ADU rules in Maryland
Representative cities: Baltimore, Annapolis.
ADU permit rule
Permit requiredCase by casecity authority
Fee basis
Building permit fee set by the city; zoning/use approval also required.
Typical timeline
Varies
Setback
—
Area threshold
Not size-exempt
Exempt if
Not exempt
Go / no-go
case-by-case
ADUs require a building permit and local zoning approval. Maryland’s MBPS governs construction; local zoning controls whether an ADU is allowed. Verify with Baltimore DHCD or Annapolis Planning & Zoning.
🧮
Estimate build cost
Model this ADU's construction cost by type, size & finish.
📊
Model rental ROI
Turn the build cost into rent, payback & 20-year cash flow.
Frequently asked questions
Do I need a permit to build an ADU in Maryland?
Per Maryland rules, an ADU is "yes" for a permit and the authority is "city". ADUs require a building permit and local zoning approval. Maryland’s MBPS governs construction; local zoning controls whether an ADU is allowed. Verify with Baltimore DHCD or Annapolis Planning & Zoning. Always confirm with the issuing building department.
How big can an ADU be in Maryland?
Size limits for an ADU in Maryland are set by local zoning — verify with your city building department.
What are the ADU setbacks in Maryland?
Setback rules vary by city in Maryland; confirm with the local planning or building department.
How much does an ADU permit cost in Maryland?
Fee basis: Building permit fee set by the city; zoning/use approval also required.
State-wide sources: Maryland Dept. of Labor — Building Performance Standards (state building code) · Baltimore City — Dept. of Housing & Community Development (permits) · City of Annapolis — Forms, Permits & Licenses
Plan the ADU numbers for Maryland
ADU build cost calculator
Estimate cost by type, floor area, state and finish level.
Rental ROI and payback
Model rent, cash flow and how long the build takes to pay for itself.
Financing comparison
HELOC vs construction loan vs home equity loan vs cash, on example rates.
Does your ADU need a permit?
Run the go / no-go checker with your own project details.