Can I Build ADU in Baltimore, MD? (2026)
Find out if you can build a adu in Baltimore, MD. Rules, permit requirements, costs, and next steps.
Yes, ADUs are allowed in Baltimore, MD. California state law ensures by-right approval.
An Accessory Dwelling Unit (ADU) is a secondary housing unit on a residential lot — also called a granny flat, in-law suite, or backyard cottage. In Baltimore, MD, ADUs are permitted by right under state law, making them one of the most accessible ways to add housing on your property. ADUs can be detached, attached to the main home, or created by converting an existing garage or accessory structure.
ADU Rules in Baltimore
ADU Rules in Baltimore: Detached ADU max size: 800 sq ft. Attached ADU max size: 35% of primary dwelling floor area. Setbacks: 3 ft side, 5 ft rear. Owner-occupancy: No owner-occupancy requirement for accessory dwelling units in Baltimore..
Costs & Fees
ADU permits in Baltimore: Total estimated permit cost: $1,500–$5,000 total permit fees. Contact the Baltimore City Department of Housing and Community Development (DHCD) — Permits and Inspections for current fee schedule.
Timeline
Baltimore City permit: typically 4-8 weeks via online permit system. Baltimore City Department of Housing and Community Development (DHCD) also has programs supporting ADU construction.
Next Steps
Next steps for building an ADU in Baltimore: 1. Review full ADU rules including size limits, setbacks, and parking. 2. Apply for an ADU permit through the Baltimore City Department of Housing and Community Development (DHCD) — Permits and Inspections at https://bldgpermits.baltimorecity.gov. 3. Hire a licensed contractor familiar with MD ADU requirements.
Baltimore City Department of Housing and Community Development (DHCD) — Permits and Inspections
Phone: (410) 396-3360
Website: https://www.baltimorecity.gov/zoning
Online Permits: https://bldgpermits.baltimorecity.gov
Frequently Asked Questions
Is Baltimore City the same as Baltimore County?
No — they are completely separate jurisdictions. Baltimore City is an independent city and not part of Baltimore County. Baltimore County is a separate county government that surrounds the city. If your property is in Baltimore City, it is governed by Baltimore City agencies, codes, and regulations. Baltimore County properties use Baltimore County's separate permitting, zoning, and planning departments. This is a common source of confusion for newcomers to Maryland.
Can I build an ADU or convert my carriage house in Baltimore City?
Yes — Baltimore City allows accessory dwelling units. Many Baltimore properties have rear carriage houses (built in the 19th-early 20th century) that are excellent candidates for ADU conversion. You'll need a building permit from DHCD. No owner-occupancy requirement, no parking required, and no significant impact fees. Baltimore DHCD has programs that may provide financial assistance for eligible ADU projects as part of the city's housing strategy.
What are Baltimore's rules for short-term rentals?
Baltimore requires a Short-Term Residential Rental License ($200/year). An inspection is required before the license is issued. Maximum occupancy is 2 persons per bedroom and you need 24/7 emergency contact availability. Maryland state sales tax plus Baltimore City hotel rental tax apply — STR platforms collect and remit these taxes. Baltimore has a robust STR market given its proximity to DC, the Inner Harbor, and major universities.
My Baltimore home was built before 1978 — what should I know about lead paint?
Baltimore has significant lead paint issues in its older housing stock. Maryland's Lead Poisoning Prevention Program has specific requirements for pre-1978 rental properties. If you're doing renovation, you must follow EPA's Renovation, Repair, and Painting (RRP) Rule for lead-safe work practices. Rental properties must be registered with the Maryland Department of the Environment and pass periodic lead inspections. Baltimore City has additional lead abatement requirements and resources through DHCD.
How does Baltimore's CHAP historic preservation review work?
Baltimore's Commission for Historical and Architectural Preservation (CHAP) reviews exterior changes to contributing structures in 22+ locally designated historic districts and portions of National Register Historic Districts. If your property is in a CHAP district, you must obtain a Certificate of Approval (CoA) before making exterior changes — including window replacement, door changes, siding, and additions. Interior changes don't require CHAP review. CHAP meetings are held monthly and most straightforward applications are approved administratively.
Are there programs to help renovate vacant Baltimore rowhouses?
Yes — Baltimore DHCD operates several programs targeting vacant properties including the Baltimore Housing Rehab Program, Vacants to Value (V2V) initiative, and Homeownership Incentive Program. Baltimore City Land Bank manages a portfolio of city-owned vacant properties for sale to developers and owner-occupants. These programs prioritize neighborhoods experiencing revitalization like Remington, Oliver, Greektown, and Cherry Hill. Contact DHCD at dhcd.baltimorecity.gov for current program availability.
Source: Baltimore City Department of Housing and Community Development (DHCD) — Permits and Inspections — Building Regulations. Last verified April 6, 2026. View source