Rental conversions in Frederick

Frederick County allows one accessory dwelling unit on a lot, inside a single-family house, in an accessory structure, or built as a separate accessory structure on a single-family lot.¹⁰ In Frederick County the owner must live in either the main house or the accessory dwelling unit, and the unit needs at least one additional parking space, which may be on the street.¹⁰

A Frederick County accessory dwelling unit of no more than 1,000 square feet, not counting decks, porches and patios, needs only a building permit through the county's portal, with no Board of Appeals hearing.³ A Frederick County accessory dwelling unit over 1,000 square feet needs a special exception from the Board of Appeals after a public hearing, typically about 90 days, and its footprint and total size may each be no more than half of the main house's, with no variance available.³

Frederick County says accessory dwelling units are meant for the ongoing housing needs of county residents, and short-term rental of one as an extended-stay hotel, Airbnb or seasonal housing is not permitted.¹⁰ The owner of a Frederick County accessory dwelling unit must file an annual statement with the Zoning Administrator confirming that the conditions it was approved under still hold, and a new owner must file a statement on its continued use.¹⁰

Maryland's HB 1466, passed in 2025, requires every county and municipality with planning and zoning authority to adopt a local law allowing ADUs on lots with a single-family detached house by October 1, 2026.¹⁷ The county's rules may change as a result, so ask the zoning office for the current version before the drawings are finished.

The City of Frederick describes accessory dwelling units as smaller, independent homes on the same property as the main house, either detached like a backyard cottage or attached like a basement or garage conversion.¹⁸ The City of Frederick allows one accessory dwelling unit per lot in its RO, R4, R6, R8, R12, R16, R20, DBO and DR districts, inside or beside a single-family house, duplex or townhouse, and requires a parking space for it unless the lot already has extra parking.¹⁶

In the City of Frederick an accessory unit inside the house may take up no more than 35% of its floor area and any new entrance must face the rear or a side away from the street, while a detached unit may be no larger than 800 square feet.¹⁶ The City of Frederick requires the owner to live in either the main house or the accessory unit, bars renting the other unit for less than 90 days, and requires a Declaration of Restriction to be recorded.¹⁶

A City of Frederick accessory unit permit costs $400 to apply for, with separate electrical, plumbing and gas, and fire sprinkler permits; the plans must generally be sealed by a Maryland-registered architect or engineer, and impact fees apply to every unit.¹⁶ In the City of Frederick, a homeowner who lives on the property may rent rooms to up to two people, and the city notes that this rule may change.¹⁸

Landlords who own rental properties in the City of Frederick must hold a valid rental license, and the city requires all rental properties to be licensed and inspected regularly under Ordinance G-23-09.⁷ The City of Frederick's rental license covers long-term and short-term leases, including renting part of a home such as a single bedroom; it costs $120 a year, mandatory licensing began in January 2024, and the city inspects a random 15% of rental units each year.¹⁹

Before a renter signs a lease for most pre-1978 housing, federal law requires the landlord to disclose known lead-based paint and hazards, share available records, hand over EPA's Protect Your Family From Lead pamphlet and include a Lead Warning Statement.²⁰ A landlord who does renovation work on pre-1978 rental housing personally needs both EPA firm and renovator certification; a landlord who hires the work out needs neither, but the firm must be Lead-Safe Certified.²¹

Maryland's ADU law doesn't change a local government's power to regulate short-term rentals, and a limit on short-term rental of an ADU isn't counted as an unreasonable limitation under the law.²² Both the county and the city limit short stays in an accessory unit, so plan on a lease rather than nightly bookings.

The 2021 IRC requires the units of a two-family dwelling to be separated by walls and floors with at least a 1-hour fire-resistance rating, or a 1/2-hour rating if the building has an automatic sprinkler system throughout.²³ The 2021 IRC requires smoke alarms in each sleeping room, outside each separate sleeping area and on every story including basements, interconnected within each dwelling unit so that one sounding sets off all of them.²³ Maryland requires residential fire sprinkler systems in all new one- and two-family dwellings, which the state's planning department says includes newly built ADUs.²⁴

More than one in four adults 65 and older fall each year.²⁵ An accessory unit meant for a parent is easiest to live in on one level with a step-free path from the parking space, which a garage or basement conversion can offer more easily than rooms over a garage. NAHB's Certified Aging-in-Place Specialist (CAPS) credential trains remodelers in home modifications for aging in place.²⁶

Calling the number on this page puts you through, on a recorded line, to one independent company that handles rental conversions in the Frederick area. The design, the schedule and the price are agreed between you and that company.

The company pays us for each call, so connecting costs you nothing, and nobody from our side calls or texts you afterward. How we make money

Look the company up with the state before any money changes hands. Maryland's Home Improvement Commission licenses home improvement contractors and salespersons, and its License Search shows whether a license is current.²⁷ The City of Frederick doesn't license home improvement contractors; they must be licensed by the State of Maryland.²⁸ Check a Maryland license

Then ask who will take out the building permit and file the zoning paperwork. In Frederick County, electrical and plumbing permits are separate from the building permit, with separate fees, and the building permit is applied for by the owner or a licensed contractor unless the applicant has a notarized letter of permission.¹⁵