Building permits in unincorporated Williamson County — north of Austin and home to Round Rock and Georgetown — are issued by Williamson County Permits & Inspections. The county adopts the 2021 International Codes for construction in unincorporated areas.
This guide covers unincorporated Williamson County permit requirements, fees, and inspections.
Williamson County is one of the fastest-growing counties in Texas. Properties within Round Rock, Georgetown, Cedar Park, Leander, or other incorporated cities must apply through those cities. This guide covers unincorporated Williamson County.
What requires a building permit in Williamson County?
In unincorporated Williamson County, building permits are required for:
Permit required
- New residential and commercial construction
- Additions and alterations
- Structural modifications
- Electrical, plumbing, and mechanical work
- Decks, pools, and accessory structures
- Change of occupancy
- Demolition
- Manufactured home placement
Typically exempt
- Painting, flooring, and cosmetic work
- Minor repairs
- Agricultural exemptions
Exemptions are narrow and scope-specific. When unsure, confirm with the building department before starting — see the penalty note below.
Get the permit issued before starting work. Building without one exposes the owner to penalties and stop-work orders. Note that exemption from a building permit does not exempt a project from zoning requirements — confirm edge cases with the building department.
Who handles permitting in Williamson County?
Williamson County Permits & Inspections handles building permits, plan review, and inspections for unincorporated areas.
| Detail | Information |
|---|---|
| Office | Williamson County Permits & Inspections |
| Phone | (512) 943-1553 |
| Covers | Unincorporated Williamson County |
| Code cycle | 2021 IBC/IRC with local amendments |
| Website | wilco.org/Departments/Permits-and-Inspections |
Contact Permits & Inspections to apply. Properties within Round Rock, Georgetown, Cedar Park, or other cities apply through those cities. For unincorporated areas, contact (512) 943-1553.
Williamson County building permit cost
Williamson County permit fees are valuation-based. Contact Permits & Inspections for current fees.
| Fee component | How it works |
|---|---|
| Residential building permit | Valuation-based |
| Commercial building permit | Valuation-based |
| Plan review fee | Included |
| Trade permits | Separate fees |
| Work-without-permit | Penalties + enforcement |
Want a precise number for a specific Williamson County project? Send us the scope and valuation and we'll return a fee estimate alongside a filing timeline.
Williamson County trade permits
State trade licenses apply.
Electrical permits
TDLR-licensed electrician required.
Plumbing permits
TSBPE-licensed plumber required.
Mechanical (HVAC) permits
TDLR-licensed mechanical contractor required.
Miscellaneous & specialty
Williamson County's rapid growth means jurisdiction boundaries change frequently. Verify current jurisdiction before applying.
Verify your contractor's license. Texas licenses electricians (TDLR), plumbers (TSBPE), and HVAC/mechanical contractors (TDLR) at the state level — contractors must register with the local municipality before pulling permits. Texas does not issue a statewide general-contractor license. Projects over $50,000 require a TDLR project number and accessibility review. The property owner is responsible for ensuring a permit is obtained. Verify trade licensure at tdlr.texas.gov and tsbpe.texas.gov.
How to get a building permit in Williamson County
Verify jurisdiction
Confirm the property is in unincorporated Williamson County.
Contact Permits & Inspections
Call (512) 943-1553 for requirements.
Submit application & plans
Provide all required documents.
Review & approval
County reviews against adopted codes.
Pay fees & receive permit
Pay all fees.
Schedule inspections through CO
Schedule inspections. Final inspection required for CO.
Inspections in Williamson County
Schedule inspections through Williamson County Permits & Inspections. Standard checkpoints include foundation, framing, rough-in MEP, insulation, and final.
Address correction notices before requesting a re-inspection; a final inspection and Certificate of Occupancy are required before legal occupancy or use.
Official Williamson County permitting resources
- 🏛️ Williamson County Permits & Inspections
- 📋 Williamson County
- 🪪 TX TDLR — licensing & regulation
- 🪪 TX TSBPE — plumbing board
Simplify Williamson County permitting with Alliance Permitting
Williamson County's explosive growth and active permitting department reward well-prepared applications. Alliance Permitting is a permit expediter for Williamson County — our permit expediting services pair AI-driven document review with experts who know the Williamson County Permits & Inspections process, so your Williamson County submissions move faster.
Trusted by leading builders and brands — including Dream Finders Homes, Tesla, Verizon, Hyatt, and Sunnova.
Contractors and builders choose Alliance for Williamson County because we deliver:
- Local expertise — we know Williamson County Permits & Inspections and the 2021 code requirements.
- Complete oversight — track every permit and inspection across all your jobs in one place.
- Error-free submissions — AI pre-checks plus expert review catch issues before they become correction cycles.
Alliance Permitting is a permit documentation and submission company: we prepare your paperwork, file it correctly, and coordinate with the building department through issuance — including preparing private-provider documentation where that option is available. We are not a contractor and do not perform licensed plan review or inspections; that work stays with your team and the jurisdiction.
Need a Williamson County building permit?
Get your Williamson County project permitted right. Alliance Permitting handles your applications.
More Texas permitting guides
This guide is provided by Alliance Permitting for general informational purposes and reflects publicly available information believed accurate as of June 2026. Permit requirements, fees, and processes change; always confirm current details with the Williamson County Permits & Inspections before filing. This is not legal advice.