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

Some Restrictions

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

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

Key Facts

District allowed: AG (Agricultural Preservation) only
Units allowed: One detached ADU
Max size: 50% of primary dwelling
Location: Side and rear yards
Driveway: Must share with primary home

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 Greenville County, SC rules below cover local size, height, and setback requirements.

Summary

In unincorporated Greenville County, one detached accessory dwelling unit is allowed alongside a principal home only in the AG (Agricultural Preservation) district. It cannot exceed 50% of the primary dwelling's square footage, must sit in a side or rear yard, and must share the primary home's driveway.

City-specific rules exist: Simpsonville has its own adu rules rules that differ from Greenville County's county-level regulations. If you live in Simpsonville, check the city-specific page instead.

Only one detached accessory dwelling unit may be permitted in conjunction with a principle dwelling in the AG, Agricultural Preservation District... The accessory dwelling unit shall not be larger than 50% of the primary dwelling's gross square footage.

Source: Greenville County Zoning AnswerBook — Single-Family Residential District rulesView official code

Full Breakdown

The Greenville County Zoning Ordinance permits a detached accessory dwelling with a principal single-family home in the AG, Agricultural Preservation District. Only one is allowed, and it must be no larger than 50% of the primary dwelling's gross square footage, located in the side and rear yards, meet the setback requirements of Article 7 (Tables 7.1 and 7.3), comply with all SC DHEC regulations, and share the primary dwelling's driveway. A manufactured home used as the accessory dwelling must meet the ordinance's manufactured-house conditions. Inside Greenville, Greer, Mauldin, Simpsonville, Travelers Rest, or Fountain Inn, the city's own zoning applies instead.

Violations & Fines

Building a second dwelling outside the AG district, or exceeding the 50% size cap, is a zoning violation enforced by Greenville County Planning and Code Compliance; correction or removal may be ordered.

Frequently Asked Questions

Can I build a second cottage on my Greenville County lot?

A detached accessory dwelling is only allowed in the AG (Agricultural Preservation) district, capped at 50% of the primary home's size and sharing its driveway. Other districts and cities do not permit it this way.

Does the ADU need a septic approval?

Yes. The accessory dwelling must meet all South Carolina Department of Health and Environmental Control (DHEC) regulations, which govern septic and water service.

Sources & Official References

[1]County of Greenville SC Zoning Ordinance (Article 6)

Other rules in Greenville County

Animal Ordinances: Dog Leash LawsSome Restrictions Shed & Carport RulesSome Restrictions Tiny HomesSome Restrictions Garage ConversionsSome Restrictions Noise Ordinances: Vehicle NoiseSignificant Restrictions Noise Ordinances: Decibel LimitsSome Restrictions Noise Ordinances: Barking DogsSome Restrictions Animal Ordinances: Exotic PetsSignificant Restrictions Animal Ordinances: Mandatory Spay/NeuterLight Restrictions

All Greenville County rules

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

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ADU Rules in Cities Across Greenville County

Simpsonville, SC