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

Florence County Code Section 30-97 allows accessory apartments only as a conditional use where the zoning tables permit them, and it is not allowed at all inside the City of Florence's own residential districts. Size is capped at 50 percent of the principal dwelling's gross floor area, or two bedrooms, whichever comes first, and the unit must be a complete living space with its own kitchen and bathroom, but it has to run on the same gas, electrical and water meters as the main house rather than separate utility accounts.

Only one accessory apartment is allowed per single-family dwelling or lot, and it cannot be added to anything other than a single-family home. In the R-1 and R-2 districts, an existing detached accessory building may instead be used to house an immediate family member needing assisted living, documented by a written affidavit reviewed by the board of zoning appeals. The R-3 district carries its own threshold: a lot must be at least 10,000 square feet before an accessory apartment can be added. Every accessory apartment must meet the underlying district's yard setback requirements, and a detached unit needs at least 20 feet of separation from the principal dwelling.

A third off-street parking space is required beyond what the main house needs, and neither the principal residence nor the accessory apartment may be a manufactured home. Non-compliant units are zoning violations subject to Section 30-274 enforcement.