In this subtitle the following words have the meanings indicated. “Accessory dwelling unit” means a secondary dwelling unit that is: on the same lot, parcel, or tract as a primary single–family detached dwelling unit; and not greater than 75% of the size of and subordinate in use to the primary single–family detached dwelling unit. “Accessory dwelling unit” includes a structure that is: separate from the primary single–family detached dwelling unit; or attached as an addition to the primary single–family detached dwelling unit. “Dwelling unit” means a single unit providing complete living facilities for at least one individual, including, at a minimum, provisions for sanitation, cooking, eating, and sleeping. “Dwelling unit” does not include a unit in a multifamily residential building. “Utility” means water or sewer disposal services provided by: a private company regulated under Division I of the Public Utilities Article; the Washington Suburban Sanitary Commission regulated under Division II of the Public Utilities Article; a sanitary commission regulated under Title 9, Subtitle 6 of the Environment Article; or a municipal authority regulated under Title 9, Subtitle 7 of the Environment Article.