Accessory Structures in Dorchester County, SC (2026)
4 rules for unincorporated Dorchester County, South Carolina.
Verified from official government sources
ADU Rules
An accessory dwelling unit needs a lot of at least 32,760 square feet under Zoning § 10.4.1, must sit behind the main house meeting the same side and rear yard setbacks, and is capped at 40% of the principal home's floor area or 900 square feet, whichever is smaller.
Dorchester County Accessory Dwelling Unit Rules
Some RestrictionsDorchester County Zoning and Land Development Standards (Ord. No. 04-13), § 10.4.1 Accessory Dwelling Units
10.4.1 Accessory Dwelling Units (a) No accessory dwelling unit shall be constructed, or established within the principal dwelling, on a lot less than 32,760 square feet in area or the minimum required for the zoning district in which it is located, whichever is greater. (b) No more than one (1) accessory dwelling unit shall be established on a single lot of record. Accessory dwelling units shal...
Shed & Carport Rules
A storage shed is a customarily incidental accessory use under Zoning § 10.3.1(m), but its size is tiered to lot area under § 10.4.2(1)(e), from 1,000 square feet on lots under 14,500 square feet up to 15,000 square feet on lots of 15 or more acres, and it must clear a 5-foot setback from every property line.
Dorchester County Shed Size & Setback Rules
Some RestrictionsDorchester County Zoning and Land Development Standards (Ord. No. 04-13), § 10.4.2(1)(e)-(f) Accessory Structures, Residential Districts
10.4.2 Accessory Structures (1) Residential Districts (e) For a lot containing less than 14,500 sq. ft., accessory structures shall not exceed 1,000 in total floor area. For a lot of 14,500 square feet or more, but less than ¾-acre, accessory structures shall not exceed 1,500 square feet in total floor area... For lots containing 15 acres or more, accessory structures shall not exceed 15,000 sq...
Garage Conversions
Converting a garage to living space in Dorchester County is a change of occupancy needing a building permit under the 2021 SC Residential Code. Adding a bathroom or bedroom on septic triggers SCDES review under Regulation 61-56.
Dorchester County Garage Conversion Rules
Some RestrictionsS.C. Code Regs. 61-56.104(2) (Onsite Wastewater Systems)
It shall be unlawful to construct, upgrade, expand, or operate an onsite wastewater system, nonwater-carried sewage treatment system, wastewater combustion system, or gray water subsurface reuse system unless the Department has issued a permit to construct and approval to operate for the specific construction and operation proposed.
Tiny Homes
A tiny house is a legal dwelling in Dorchester County only if built to the 2021 SC Residential Code, which adopts Appendix AQ for homes 400 square feet or less. A tiny house on wheels is treated as an RV, not a permanent home.
Dorchester County Tiny Home & Small Dwelling Rules
Some Restrictions2021 South Carolina Residential Code, Appendix AQ (Tiny Houses) §§ AQ101.1, AQ102.1
This appendix shall be applicable to tiny houses used as single dwelling units. ... TINY HOUSE. A dwelling that is 400 square feet (37 m2) or less in floor area excluding lofts.
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