The Central Texas barndominium permit directory
Six counties, one row each. The building permit answer is what the county's own official site showed on the date printed, with the source linked; nothing is upgraded past what the county said. The septic, floodplain and driveway offices are the ones each county names. Inside city limits, the city's own building department applies whatever the county does.
| County | Building permit outside city limits | Septic (OSSF) | Floodplain | Driveway onto a county road | Who to call | Source |
|---|---|---|---|---|---|---|
| Llano CountyLlano | A county permit is required before you build outside city limits, and the county does not inspect the structure outside a flood hazard area. Read at the county’s own pages 2026-09-13 | Llano County Development Services, or the Lower Colorado River Authority inside its water quality zone, 325-247-2039 (The county is the state’s authorized agent and permits every system whatever the tract size. The county’s subdivision rules point lots inside the river authority’s zone at that agency’s rules) | Llano County Development Services, for the county Floodplain Administrator, 325-247-2039 (A floodplain development permit is required for any development in a special flood hazard area) | The county commissioner for your precinct, in writing, plus a county road cut permit (Nothing may be installed on a county right of way, driveways and culverts included, without the precinct commissioner’s written permission) | Llano County Development Services, 325-247-2039 | Llano County Development Services, read 2026-09-13 |
| Burnet CountyBurnet | A county permit is required before you build outside city limits, and the county does not inspect the structure outside a flood hazard area. Read at the county’s own pages 2026-09-13 | Burnet County Development Services, or the Lower Colorado River Authority inside its water quality zone, 512-715-5260 (The county permits and inspects every on-site system whatever the size of the tract, which sets aside the state acreage exception. The county publishes a link to the river authority’s jurisdiction map and does not say which lake lots fall inside it) | Burnet County Development Services, for the Floodplain Administrator appointed by Commissioners Court, 512-756-5445 (One foot of freeboard above base flood elevation is required and two feet is recommended in an A zone) | The county commissioner for your precinct, on a county road access permit (The commissioner sets culvert location, length and diameter at a site meeting, and driveway approval must be in hand before a 911 address is assigned. TxDOT approves a driveway onto a Farm to Market, Ranch Road or State Highway) | Burnet County Development Services, 512-715-5260 | Burnet County On-Site Sewage Facilities and Development Services, read 2026-09-13 |
| Williamson CountyGeorgetown | The county states it issues no building permits for the unincorporated county. Other county permits still apply. Read at the county’s own pages 2026-09-13 | Williamson County Engineer’s Office, the on-site sewage facility program, 512-943-3330 (The state authorized the County Engineer to run the program. Applications go through the county’s online portal only, and a Certificate of Compliance has to be processed first) | Williamson County Engineer’s Office, the county Floodplain Administrator, 512-943-3330 (A floodplain development permit is required in or next to the 100-year floodplain, a structure sits at least a foot above the base flood elevation, and a licensed surveyor files a FEMA elevation certificate twice, after the slab and at completion) | Williamson County Road and Bridge Division, on a county driveway permit (Required for a new or modified driveway onto a county-maintained road, with the county sizing the culvert) | Williamson County Engineer, Road and Bridge Division, 512-943-3330 | Williamson County frequently asked questions, County Engineer, read 2026-09-13 |
| Travis CountyAustin | A county permit is required before any development outside city limits, and inspections are required during the build. Read at the county’s own pages 2026-09-13 | Travis County TNR, the state’s authorized agent for the unincorporated county, or the Lower Colorado River Authority near Lake Travis, 512-854-4438 (The county states no lot-size exemption at all: every system in its jurisdiction is covered whatever the size of the lot, and the minimum lot size for a home on a septic system is one acre) | Travis County TNR, the county Floodplain Administrator (Full architectural and site plans, lowest floor elevations and a flood venting plan, an elevation certificate before framing starts and a finished-construction certificate within 30 days, and no effect on the base flood elevation) | Travis County TNR for a county-maintained road, TxDOT for a state road (The county issues no permit for a driveway onto an unmaintained or unaccepted road. Approaches are concrete, meet the road at about 90 degrees, and use corrugated metal culvert pipe at least 18 inches across) | Travis County TNR Development Services permit desk, 512-854-4215 | Travis County Transportation and Natural Resources, Development Services, read 2026-09-13 |
| Bastrop CountyBastrop | A county permit is required before any development outside city limits, and inspections are required during the build. Read at the county’s own pages 2026-09-13 | Bastrop County Environmental and Sanitation, the state’s authorized agent, 512-581-4042 (Every septic installation or modification needs a county permit regardless of acreage, which sets aside the state acreage exception. Minimum lot size is half an acre with a public water supply and one acre without one) | Bastrop County Floodplain Administrator, inside Development Services, 512-581-7159 (Two feet of freeboard above base flood elevation, extended to some Zone X areas where base level engineering has set flood depths, with a surveyor certifying the elevation) | Bastrop County Development Services, engineering inspector, for a county-maintained road; TxDOT for a state highway, 512-581-4039 (The driveway is part of the same county development application) | Bastrop County Development Services, 512-581-7176 | Bastrop County Development Services, read 2026-09-13 |
| Caldwell CountyLockhart | A county permit is required before you build outside city limits, and the county does not inspect the structure outside a flood hazard area. Read at the county’s own pages 2026-09-13 | Caldwell County Sanitation Department, the state’s authorized agent, 512-398-1803 (The county requires an application, permit and inspection whatever the size of the tract, which sets aside the state acreage exception. Minimum lot size is one acre, only a licensed installer may build the system, and the septic permit is one of the papers the construction permit needs) | Caldwell County Director of Sanitation, the county Floodplain Administrator, 512-398-1803 (A floodplain development permit is required for all construction and other development in the mapped flood zones, manufactured homes included) | Caldwell County Unit Road Department, 512-398-7269 (A driveway permit stays in force even on a tract exempt from platting) | Caldwell County Sanitation and Development Services, 512-398-1803 | Caldwell County Development Ordinance, revised February 14, 2023, read 2026-09-13 |
What applies in every row?
A septic permit on every lot without sewer, from the county or from the river authority where the lot sits inside its lake zone, after a site evaluation and with a state-licensed installer. Floodplain review wherever any of the parcel is in a mapped flood hazard area. A driveway or culvert permit for a new entrance onto a county road. And no builder license anywhere in Texas, so the contract, the insurance certificate and the engineered plans carry the standard.
Source: Office of the Texas Governor, Business Permit Office, Texas Business Licenses and Permits Guide, read 2026-09-13.
Source: LCRA On-Site Sewage Facilities Program, read 2026-09-13.
Why is the answer different in every county?
Because Texas leaves most residential building rules outside city limits to each county, and each of these six decided for itself. The permit guide explains what that means for a build.
How is this table kept honest?
A row changes only when the county's own document is read or a call to the county is logged with the date. A row that says confirm with the county says so because the county's site did not state the rule, and nobody here has guessed. If you work for one of these counties and the row is wrong, email the address in the footer with the county's page and it will be corrected and re-dated.
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Last reviewed 2026-09-13.