A Homeowner's Guide to Building Backyard Cottages, Guest Houses, and Secondary Homes
Accessory Dwelling Units (ADUs) are becoming an increasingly popular housing option for homeowners looking to maximize their property's potential. Whether you're interested in building a backyard cottage for aging parents, creating additional living space for family members, or generating rental income, an ADU can provide flexibility and long-term value.
But are ADUs actually allowed in York County, South Carolina?
The short answer is yes! York County permits accessory dwelling units in many residential zoning districts, although there are specific requirements regarding size, parking, property ownership, and building design.
If you're considering building an ADU in Rock Hill, Fort Mill, Clover, York, Lake Wylie, or an unincorporated area of York County, here's what you need to know before getting started.
What Is an Accessory Dwelling Unit (ADU)?
An Accessory Dwelling Unit is a secondary residential living space located on the same property as a primary home.
Unlike a traditional detached garage or storage shed, an ADU provides independent living accommodations, including a kitchen, bathroom, sleeping area, and living space.
Common types of ADUs include:
Detached backyard cottages: Small, standalone houses constructed behind or beside the primary residence.
Garage apartments: Living spaces constructed above or within a garage.
Attached ADUs: Secondary living quarters built as an addition to the existing home.
Interior conversions: Portions of an existing home converted into independent living quarters.
ADUs can provide homeowners with additional housing options without requiring the purchase of a separate property.
Are ADUs Legal in York County, South Carolina?
Yes. Under York County's zoning ordinance, accessory dwelling units are permitted as an accessory use to single-family detached homes in several zoning districts.
According to Section 155.630 of the York County Zoning Code, ADUs are allowed in the following districts:
AGC, AGC-I, RUD, RUD-I, RSF-40, RSF-30, RMX-20, RMX-10, RMX-6, and MU.
However, these regulations apply to properties under York County's zoning jurisdiction. Properties located within incorporated municipalities, such as Rock Hill, Fort Mill, Clover, or York, may be subject to different zoning requirements.
Before beginning your project, it's important to verify your property's zoning classification and confirm that an ADU is permitted.
How Big Can an ADU Be in York County?
One of the most important considerations when planning an ADU is its size.
Under York County's published ADU regulations, the secondary dwelling must meet two primary requirements:
Minimum size: 400 square feet
Maximum size: 50% of the primary home's habitable floor area
For example:
Primary Home Size Maximum ADU Size
1,000 sq. ft. 500 sq. ft.
1,200 sq. ft. 600 sq. ft.
1,500 sq. ft. 750 sq. ft.
2,000 sq. ft. 1,000 sq. ft.
2,500 sq. ft. 1,250 sq. ft.
These calculations are based on habitable floor area, not necessarily the total square footage of the structure.
For homeowners interested in building a small cottage, a 400–600-square-foot ADU can provide a functional living space with a bedroom, bathroom, kitchen, and living area.
Additional zoning restrictions, setbacks, and building requirements may further limit the size or placement of the structure.
Do You Have to Live on the Property?
Yes. Under York County's ADU regulations, the property owner must maintain their primary residence on the lot.
However, the owner may live in either the primary house or the accessory dwelling unit.
For example, a homeowner could build a small backyard cottage, move into it, and allow a family member to occupy the larger primary residence.
Alternatively, the homeowner could continue living in the primary house and use the ADU as a rental property, subject to applicable rental regulations.
This owner-occupancy requirement is important for anyone considering an ADU strictly as an investment property.
Can You Rent Out an ADU in York County?
An ADU may provide an opportunity to generate rental income, but homeowners should confirm the rental requirements that apply to their property.
For example, a homeowner may want to construct a one-bedroom backyard cottage and rent it to a long-term tenant.
Before proceeding, it's important to verify applicable zoning rules, lease restrictions, HOA covenants, and any short-term rental regulations.
Because York County requires the property owner to maintain their primary residence on the lot, ADUs should not automatically be treated as unrestricted investment properties.
Are Tiny Houses Allowed as ADUs?
This is an important distinction for homeowners interested in tiny homes.
York County's published zoning regulations specifically prohibit tiny houses on wheels, recreational vehicles, travel trailers, campers, and manufactured homes from being used as accessory dwelling units.
However, a small cottage constructed on a permanent foundation may qualify as an ADU if it meets applicable zoning and building requirements.
For example, a 500-square-foot cottage with a permanent foundation, kitchen, bathroom, and sleeping area could potentially qualify as an ADU on an eligible property.
The key difference is that the home must be constructed and permitted as a residential dwelling rather than treated as a recreational vehicle or temporary structure.
What Are the Parking Requirements?
York County requires at least one additional off-street parking space for each bedroom in an ADU.
This parking must be provided in addition to the parking required for the primary residence.
For example, if you construct a one-bedroom backyard cottage, you would generally need to provide one additional off-street parking space.
Homeowners should account for these requirements when determining where an ADU can be located on their property.
Does the ADU Have to Match the Main House?
Yes. York County's published regulations require an ADU to have a similar architectural appearance to the primary residence.
This includes similar:
Roof pitch
Roofing materials
Siding materials
Exterior color palette
For detached ADUs, the structure's height is also limited relative to the primary home.
These requirements are intended to help accessory dwellings complement the appearance of existing residential neighborhoods.
Can You Build an ADU in Rock Hill, Fort Mill, or Clover?
Although these communities are all located within York County, their zoning regulations are not necessarily the same.
Rock Hill, SC
The City of Rock Hill has its own zoning ordinance governing accessory dwelling units. Homeowners should verify permitted uses, minimum dwelling sizes, parking, and owner-occupancy requirements with the city's Planning and Development Department.
Fort Mill, SC
The Town of Fort Mill also regulates accessory dwelling units through its municipal zoning ordinance. Depending on the property's zoning district, garage apartments, guest houses, and other accessory residential structures may be permitted subject to specific requirements.
Clover, SC
Properties located within the Town of Clover are subject to municipal zoning regulations. Homeowners should confirm whether an ADU is permitted on their specific lot before purchasing plans or beginning construction.
Lake Wylie and Unincorporated York County
Many properties in Lake Wylie and other unincorporated communities fall under York County's zoning jurisdiction. However, neighborhood covenants, HOA restrictions, waterfront buffers, and other development limitations may affect whether an ADU can be constructed.
The most important first step is determining which local government has zoning authority over your property.
Do You Need a Building Permit for an ADU?
Yes. Constructing a new ADU generally requires building permits and zoning approval from the applicable jurisdiction.
For properties under York County's jurisdiction, the county provides a dedicated residential ADU permit application.
The permitting process may require:
A site plan showing the proposed ADU, property boundaries, setbacks, easements, and driveway.
Construction drawings showing the layout, foundation, framing, and other building components.
Verification of zoning compliance.
Water and sewer connection information or septic system approval.
Applicable building, electrical, plumbing, and mechanical permits.
Required inspections before the dwelling can be occupied.
Properties near Lake Wylie or the Catawba River may also require additional site-plan information related to waterfront buffers and elevation restrictions.
Before purchasing building plans, homeowners should confirm that their property can accommodate the proposed structure.
What About Water, Sewer, and Septic Systems?
Utility connections are another important consideration when building an ADU.
If your property is served by public water and sewer, you will need to determine whether the existing services can accommodate an additional dwelling or whether separate connections and fees are required.
For properties using a septic system, adding an ADU may require an evaluation of the existing system's capacity and approval from the appropriate permitting authorities.
In some cases, utility improvements can represent a significant portion of the project's overall cost.
Understanding these requirements early can help avoid unexpected expenses during construction.
What Are the Benefits of Building an ADU?
ADUs offer several advantages for homeowners throughout York County.
Multigenerational living: A backyard cottage can provide independent living accommodations for aging parents or adult children while keeping family members close.
Potential rental income: Depending on local regulations, homeowners may be able to rent an ADU to a long-term tenant.
Flexible living arrangements: An ADU can accommodate changing family needs without requiring a move to a larger property.
Efficient use of land: Building a secondary dwelling allows homeowners to make better use of an existing residential lot.
Potential property value: A legally permitted ADU may make a property more attractive to certain buyers, although the effect on resale value varies by location and market conditions.
Building an Energy-Efficient ADU in York County
One advantage of constructing a new ADU is the opportunity to incorporate modern energy-efficient building practices.
Because many ADUs are relatively small, thoughtful design and construction can help reduce energy consumption while creating a comfortable living environment.
Features such as high-performance insulation, energy-efficient windows, proper air sealing, and efficient mini-split heating and cooling systems can make a substantial difference.
Homeowners may also consider pursuing ENERGY STAR certification for eligible new construction projects.
An energy-efficient backyard cottage can offer lower operating expenses, improved indoor comfort, and better management of indoor air quality and humidity.
Build Your ADU With Burns Custom Homes
At Burns Custom Homes, we believe small homes can make a big difference.
We specialize in thoughtfully designed homes that maximize functionality, comfort, and energy efficiency. Whether you're considering a backyard cottage for family members, a small rental home, or additional living space on your property, we're passionate about helping homeowners explore practical housing solutions.
Our goal is to make the building process easier to understand, from evaluating your property's potential to planning and constructing a home that meets your needs.
Interested in building an ADU in Rock Hill, Fort Mill, York, Clover, Lake Wylie, or the surrounding York County area?
Contact Burns Custom Homes to discuss your property, explore small-home designs, and learn more about the process of building an accessory dwelling unit.
Disclaimer: Zoning regulations and building requirements vary by jurisdiction and may change. The York County requirements discussed above are based on publicly available county regulations and permitting guidance reviewed in October 2026. Property owners should verify current requirements with their local zoning and building departments before beginning a project.