Compare ADU zoning rules across 1 South Carolina cities. Average ADU score: 6.0/10.
Gathered from the 1 city below, with the bill or ordinance each one names. Statewide measures are listed once with the cities they reached, rather than repeated for each.
Statewide law sets a floor; the numbers that decide your project are local. Here is the spread across the 1 South Carolina city covered here, taken from each city's own ordinance rather than a state summary.
| Question | Across South Carolina |
|---|---|
| Are ADUs permitted? | 1 of 1 permit them. |
| Detached size cap | Median 600 sq ft, from 600 to 600 sq ft across the 1 cities publishing a numeric cap. |
| Owner-occupancy | Required in 1 of 1. |
| Build cost | $140,000 to $300,000 depending on city and unit type. |
Recomputed whenever a city page changes, so this and the city pages below cannot disagree.
1 of the 1 South Carolina city we cover permit ADUs. Whether yours is allowed depends on your city’s code and your lot; the table below links to each city.
Detached size caps run from 600 to 600 sq ft across the 1 South Carolina cities that publish a number; the median is 600 sq ft. Many cities also cap an ADU at a share of the main house.
1 of the 1 cities we cover require it; the rest do not. Check the city page for yours.
$140,000 to $300,000 depending on the city and the type of unit, from each city’s own cost guide.
You apply to your city’s building department for a building permit (or to the county, if the lot is outside city limits). Each city page lists its own process, fees and published review times.
| City | Max Size | Setbacks | Permit Fees | Build Cost | 1BR Rent | Score |
|---|---|---|---|---|---|---|
| Charleston | 850 sq ft of conditioned floor area (Sec. 54-214.e). If the accessory building uses the reduced side/rear setback exception in Sec. 54-506(f), its building footprint is capped at 600 sq ft instead. | The district's accessory-building rear setback applies. Sec. 54-506(f) lets a qualifying accessory building with a footprint of 600 sq ft or less sit closer to an interior rear line (3 ft as read from the code in July 2026; Municode could not be re-read on Sept. 20, 2026, so confirm the distance and which lot lines qualify with the Zoning Desk). | Valuation-based (fee schedule eff. Oct. 1, 2019): $40 application + permit fee ($260 + $4 per $1,000 over $50,000; $460 + $3 per $1,000 over $100,000) + plan review at 50% of the permit fee. An 850 sq ft ADU at the schedule's $116.15/sq ft is about $724 before trade permits; budget $700-$1,300. | $140,000-$300,000 | $1,550-$1,750/mo | 6/10 |
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