Rockville, MD Accessory Structures: ADU Rental Restrictions (2026)
Key Facts
- Rule
- only 1 unit per lot licensed
- Governs
- single unit + accessory apartment
- ADU standards
- § 18-129 min. facilities
- Citation
- Rockville City Code § 18-112
Summary
Rockville, Maryland bars a landlord from holding rental licenses for both a house and its accessory apartment at once: only one of the two units on a lot may be licensed for rent at a time.
Where a single dwelling unit contains, or is attached to an accessory apartment, a single dwelling unit rental license may only be issued for that part of the building excluding the accessory apartment. In no case may a rental license be issued for a single dwelling unit and for an accessory apartment on the same lot;(4)Accessory apartment rental unit license. No license may be issued for an accessory apartment where another rental residential use exists on the same lot. (Laws of Rockville, Ch. 26, § 3-102; Ord. No. 25-90, § 2, 9-10-90; Ord. No. 8-09, § 3, 3-9-09)
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Code of Ordinances: Supplement 17 Update 1).
Full Breakdown
Under City Code § 18-112, a single dwelling unit rental license covers only the main house when an accessory apartment is attached, and in no case may a rental license be issued for both a single dwelling unit and an accessory apartment on the same lot. Conversely, no accessory apartment rental license may issue if another rental residential use already exists on that lot. Rockville, which runs its own Planning Commission and Zoning Ordinance independent of Montgomery County, also requires every licensed accessory apartment to meet minimum facility standards under § 18-129, including its own bathroom, cooking facilities, a safe means of egress, and an operable smoke detector.
Violations & Fines
Renting out both the primary unit and the accessory apartment on the same lot without separate authorization violates the licensing scheme and can result in license denial or revocation.
Frequently Asked Questions
Can I rent out both my house and its accessory apartment in Rockville?
What must a Rockville accessory apartment have to be licensed for rent?
Sources & Official References
Other rules in Rockville
Compare Rockville to another location·View the Maryland accessory structures overview
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