ADU Guide · Verified 2026
Building an ADU in South Carolina
South Carolina has no statewide ADU mandate, and each municipality sets its own rules. A pending bill takes a genuinely different approach from most states in this research, offering a property tax exemption for ADUs rented to lower-income tenants rather than requiring cities to allow ADUs at all.
Quick Facts
Statewide floors set by No statewide ADU mandate; Bill 3469 (property tax incentive) pending. Your city may be more generous but cannot go below them.
The Three Types of ADU
A real bill, but a genuinely different kind of law
Most states in this research reformed ADU rules through zoning preemption, requiring cities to allow ADUs. South Carolina's pending Bill 3469 takes a different approach entirely: a property tax exemption for ADUs rented to lower-income tenants, an economic incentive layered on top of local zoning rather than a mandate that changes what zoning allows in the first place.
It still requires local approval first
Bill 3469's tax exemption is conditional on the ADU already complying with local zoning ordinances, meaning it only helps in cities that already permit ADUs; it does nothing for a homeowner in a city that doesn't allow ADUs at all.
What people get wrong
The most common mistake is assuming Bill 3469, if it passes, would legalize ADUs statewide. It wouldn't, it only changes the tax treatment of an ADU that's already legal under local zoning, a real and important distinction from a zoning-preemption law.
From Idea to Move-In: The Timeline
Who Administers It
Building It Yourself? Here's What You'll Need
Planning an ADU? Tools homeowners use in the design and layout phase:
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Check Your Local Rules
Your city may allow more than the state floor
State law sets the minimum; many South Carolina cities and counties are more generous. Browse the full directory of 46 counties and every city in South Carolina for local rules, fees, and building department contact details.
Browse the full South Carolina directory →Not sure if your project needs a building permit, a zoning approval, or both? See our guide to building permits vs. zoning approval.
Official Sources
ADU law changes frequently and local ordinances add detail. This guide is general information, not legal advice, always confirm with your local building department. Reviewed by the StateDataIndex Editorial Team · Updated September 2026.