Anderson County, SC Accessory Structures: ADU Rules (2026)

Section 7:10, Accessory dwelling, does not create a general right to build a garage apartment or in-law suite on a single-family residential lot. Instead, it allows one accessory dwelling unit with approval of the board of zoning appeals in conjunction with any permitted principal use, but only in the S-1 (Service), I-1 (Industrial), C-1, and C-2 commercial districts, not in any residential zoning district. Three conditions apply: the accessory dwelling unit must be located entirely within the structure containing the permitted principal use, meaning it cannot be a freestanding building; it must be clearly incidental and subordinate to, and necessary for, the operation of that principal use, the classic example being caretaker or on-site manager housing tied to a commercial or industrial operation; and it cannot interfere with the principal use's operation, nor can that use create conditions hazardous or adverse to the people living in the accessory unit.

Because approval runs through the board of zoning appeals rather than a staff permit, an applicant must go through the special exception process in Article 9, including a public hearing noticed at least 15 days in advance, referral to a zoning advisory group for recommendation, and a $200 application fee under Section 9:8. Residential-district homeowners looking to add a second dwelling unit, such as for an aging parent, will not find authority for that in Section 7:10; the researched general-provision sections in Articles 6 and 7 do not extend this allowance to residential lots.