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

Some Restrictions

Compiled from the official code textEditor Martyn O'NeillLast verified September 2026

ADU rules in Spartanburg County, SC, also called accessory dwelling unit regulations or granny flat ordinances, cover setbacks, owner-occupancy, parking, and permit requirements.

Key Facts

Max ADU size: One-third of principal dwelling floor area
Type allowed: One detached accessory dwelling unit
Governing code: ULMO Section 3.05
Setbacks: Must meet ULMO Table 3
Applies to: Unincorporated ULMO areas only

ADU Eligibility Quick-Check

An Accessory Dwelling Unit (ADU) is a smaller, independent living unit on the same lot as a single-family home: converted garages, detached cottages, basement or attic conversions, and attached additions all qualify. Most states have streamlined ADU permitting since 2020, but local rules still control size, height, and setback.

Is your lot zoned single-family or multi-family residential?
Does your lot have at least 1,200 sq ft of buildable space?
Is your existing home owner-occupied (in most states this is not required, but some require it for ADU permits)?
Will the ADU stay under your state's size cap (commonly 850-1,200 sq ft for detached)?
Can you provide one off-street parking space (waived in many states within 0.5 mi of transit)?

If you answered 'yes' to most of these, you likely qualify in South Carolina under recent ADU streamlining laws. The Spartanburg County, SC rules below cover local size, height, and setback requirements.

Summary

In areas governed by the Unified Land Management Ordinance, a single detached accessory dwelling unit (ADU) is permitted so long as it is no larger than one-third of the principal home's floor area and meets the Table 3 dimensional and setback requirements.

These county ordinances apply to unincorporated areas of Spartanburg County. Incorporated cities within the county may have their own rules that take precedence over county-level regulations.

A single detached accessory dwelling unit no greater than 1/3 the floor area of the principal dwelling may be permitted, provided all applicable requirements of Table 3 are met and other public agencies have been satisfied.

View official code

Official source re-checked September 8, 2026: the cited page had not changed since it was quoted.

Full Breakdown

Spartanburg County's ULMO governs the unzoned/ULMO portion of the unincorporated county. Section 3.05 permits one detached accessory dwelling unit provided it does not exceed one-third of the principal dwelling's floor area, meets all Table 3 setback and lot requirements, and other public agencies (septic, building codes) are satisfied. A second residential structure requires prior county approval before any address is assigned or building permit issued. The Southwest Planning Area follows the separate Performance Zoning Ordinance instead. Incorporated cities such as Spartanburg, Greer, and Duncan set their own ADU rules. Contact Planning & Development (864-596-3570) to confirm which ordinance applies to your parcel.

Violations & Fines

Building or occupying a second dwelling or ADU without prior county approval and a building permit is a zoning violation subject to stop-work orders and County enforcement.

Frequently Asked Questions

How big can my accessory apartment be?

No greater than one-third of your principal dwelling's floor area, and it must meet all Table 3 setback and dimensional requirements.

Do I need county approval for a second home on my lot?

Yes. A second residential structure requires documented prior approval before any address is assigned or building permit issued.

Sources & Official References

Other rules in Spartanburg County

Noise Ordinances: Quiet HoursSome Restrictions Animal Ordinances: Dog Leash LawsSome Restrictions Shed & Carport RulesSome Restrictions Tiny HomesSome Restrictions Garage ConversionsSome Restrictions Noise Ordinances: Amplified Music & Outdoor SoundSome Restrictions Noise Ordinances: Aircraft NoiseFew Restrictions Noise Ordinances: Barking DogsSome Restrictions Animal Ordinances: Exotic PetsHeavy Restrictions

All Spartanburg County rules

How Spartanburg County compares: Easiest Cities to Build an ADU·Compare Spartanburg County to another location·View the South Carolina accessory structures overview

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