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Accessory Structures in Gaithersburg, MD (2026)

2 verified accessory structures rules for Gaithersburg, Maryland, sourced directly from the municipal code and official government pages.

Verified from official government sources

ADU Rules

Gaithersburg allows one accessory dwelling unit per single-family lot under section 24-5.2 of the zoning code. A detached ADU is capped at 800 square feet, or 1,200 square feet with planning commission site-plan approval, while an attached or integral ADU cannot exceed 49 percent of the primary structure's gross floor area. The unit cannot be rented short-term.

Gaithersburg Accessory Dwelling Unit Rules

Some Restrictions

Gaithersburg City Code § 24-5.2

(C)Number restricted. Where accessory dwelling units are allowed, not more than one accessory dwelling unit shall be allowed on a lot, parcel, or tract of land associated with a single-family residential dwelling. ... (E)Applicable standards. ... (4)Accessory dwelling units that are integral or attached to the primary structure shall not exceed forty-nine (49) percent of the gross floor area of...

Shed & Carport Rules

Gaithersburg keeps accessory structures like sheds out of the front yard, sets a 2-foot setback for structures 200 square feet or smaller and 10 feet for anything larger, and caps most accessory buildings at 800 square feet and 15 feet in height, all under the zoning code's accessory-structure section.

Gaithersburg Shed Size and Setback Rules

Some Restrictions

Gaithersburg City Code § 24-6.4(B)(1)-(5)

(2)Setbacks.(a)Accessory structures two hundred (200) square feet or less in area shall not be less than two (2) feet from any lot line.(b)Accessory structures of more than two hundred (200) square feet in area shall not be less than ten (10) feet from any lot line, unless approved by the planning commission.(3)Lot coverage. All accessory structures must comply with the maximum building and imp...

Looking for Montgomery County county-wide rules?

County ordinances apply to unincorporated areas and may supplement Gaithersburg city rules.

Accessory Structures in Montgomery County