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

Significant Restrictions

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

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

Key Facts

Size cap: 25% of primary home, max 850 sq ft
Occupancy rule: No rent-paying occupants allowed
Lot requirement: Must be on same lot as main house
Status in R1-R5 zones: Accessory use, no separate permit hearing
Unrestricted detached ADU in R1-R2-R(F): Prohibited outright
General zoning penalty: Up to $500 fine / 30 days per § 20.6

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

Summary

Berkeley County's zoning ordinance caps a garage apartment or guesthouse at 25 percent of the main home's heated square footage, up to 850 square feet, and lets residents build one as an accessory use in nearly every residential zone, but only if no rent is charged. A stand-alone, unrestricted accessory dwelling unit is banned in the county's core single-family districts.

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

2.3.51. Garage apartment. An accessory dwelling unit with separate kitchen, bathing, and sleeping areas located above or within the garage of the principal dwelling unit that is no larger than 25 percent of the primary structure's heated square footage, up to a maximum of 850 square feet. Such dwelling unit shall be located on the same lot as the primary structure. In residential districts, a garage apartment shall be used only for the housing of individuals who do not pay any form of consideration in exchange for residing therein.

View official code

Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Code of Ordinances: Supplement 37).

Full Breakdown

The zoning ordinance's definitions article draws a sharp line between two kinds of secondary units. 1 applies those definitions across all sixteen zoning districts: a "Guesthouse/garage apartment" is coded "a" (accessory use) in R1, R1-MM, R2, R3, R4, R5, R1-R, R2-R, R2-R(F), R15, RNC, GC and OI, conditional ("c") in the Flex1 district, and prohibited ("x") in the light- and heavy-industrial districts. 51 without special approval, but cannot add an unrestricted detached ADU without a conditional-use hearing or a rezoning to a district that allows it.

Violations & Fines

A garage apartment or guesthouse that exceeds the 25 percent/850-square-foot cap, or that is rented out for consideration, no longer qualifies under section 2.3.51 and becomes an unpermitted use. Because zoning enforcement in this ordinance is countywide, an oversized or rented unit falls under the general violation and penalty sections 20.5 and 20.6: the zoning administrator can order the violation stopped, and a conviction carries a misdemeanor fine of up to $500, up to 30 days in jail, or both, with each day of continued violation a separate offense.

Frequently Asked Questions

Can I build a garage apartment on my Berkeley County property?

Yes, in most residential zones. Section 2.3.51 lets a garage apartment be built as an accessory use on the same lot as the main house, capped at 25 percent of the primary home's heated square footage or 850 square feet, whichever is smaller, as long as no one living there pays rent.

Can I rent out an accessory dwelling unit in Berkeley County?

No. Section 2.3.51 requires that a garage apartment or guesthouse "be used only for the housing of individuals who do not pay any form of consideration in exchange for residing therein," so renting it out takes it outside the zoning definition entirely.

Are detached accessory dwelling units allowed everywhere in the county?

No. The use table at section 4.3.1 prohibits a generic, size-unrestricted "accessory dwelling unit" in the R1 through R2-R(F) single-family districts, allowing it only as a conditional use in the R15 and Flex1 districts or as an accessory use in a few nonresidential zones.

Sources & Official References

[1]Berkeley County Code of Ordinances, Appendix A, Art. 2 §§ 2.3.4, 2.3.51

Other rules in Berkeley County

Noise Ordinances: Quiet HoursSome Restrictions Noise Ordinances: Construction HoursSome Restrictions Shed & Carport RulesSome Restrictions Noise Ordinances: Amplified Music & Outdoor SoundSome Restrictions Noise Ordinances: Vehicle NoiseSome Restrictions Noise Ordinances: Barking DogsSome Restrictions Parking Rules: Commercial & Oversized VehiclesSome Restrictions

All Berkeley County rules

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

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