Forsyth County, GA Accessory Structures: ADU Rules (2026)

2, but never both, and never combined with a home occupation, professional home office, or a hardship manufactured/mobile home on the same lot. Both types share the same floor-area rule: at least 400 square feet of heated space per occupant, with the apartment's total heated area running no less than 400 square feet and no more than 1,000 square feet or the size of the principal dwelling, whichever is smaller. Each apartment requires one additional off-street parking space located in a side or rear yard, and its entrance must face a side or rear yard, never the street the main house fronts.

Exterior finishes and architectural treatments, brick, wood, stucco and similar materials, must substantially match the principal dwelling. The Forsyth County Health Department has to certify that water, sanitary sewer, or septic facilities can adequately serve both the main house and the accessory unit before it can be occupied. The two apartment types diverge on density and placement: an attached accessory apartment does not count toward density calculations, while a detached one does, and a detached unit must sit in a rear yard unless it is built into an existing accessory structure like a garage. A detached accessory apartment that is a manufactured home must also meet the code's manufactured-home standards.