Building permits, zoning and septic rules in McMullen County, Texas

McMullen County's published permit materials do not establish a general countywide building permit for a home¹. New construction, additions, relocations, demolitions, replacements and manufactured-home placement within, partially within, or adjacent to a mapped area of special flood hazard do need a floodplain development permit, returned to the County Judge's office². The application fee is printed on the county's current floodplain form, so check the amount there before filing⁹. The same application asks for plans drawn to scale and, near a flood hazard area, certifications from a Texas registered engineer, architect or surveyor¹⁰.

Outside a mapped flood hazard area, Texas law does not give most counties general building-code authority: only a county with a population over 250,000, or one adjacent to such a county, may adopt a fire code covering commercial buildings and larger residential buildings¹¹. McMullen County's population is about 568 people, far below that threshold, so this state authority does not reach it¹². We could not confirm whether the county runs building inspections or issues certificates of occupancy; ask the County Judge's office.

The McMullen County Judge's office administers floodplain development permits, and the county's own materials name this office as where a flood-zone application is returned^1,9. Reach the office at 361-274-3900, 501 River Street, Tilden, Texas 78072⁹. McMullen County has no separate building, zoning or planning department -- for anything outside floodplain development and OSSF (septic) permitting, ask the County Judge's office directly, since county materials do not name a different permitting office⁹.

McMullen County has adopted no zoning ordinance, and no county rule sets minimum lot size, setbacks, lot coverage, building height or accessory dwellings for unincorporated land³. The county does regulate subdivisions: its permits page links to the county Subdivision Regulations, so check them before dividing a tract into smaller lots⁶. The county page does not summarize those standards, so ask the County Judge's office for the current document.

McMullen County requires a permit to construct, install, alter, extend or repair an on-site sewage facility (OSSF), administered through the county's OSSF program⁵. Septic permits are separate from floodplain permits and come from the OSSF program, not the County Judge's floodplain review⁴. The permitting authority may enter the property to evaluate the lot and inspect the system, and a permit to operate is granted only after a successful inspection⁴. Reach the McMullen County OSSF program at 361-449-8043⁴. Texas's statewide 10-acre rule can remove the permit requirement for a single-family home, but it requires a site evaluation by a TCEQ-licensed Site Evaluator or Professional Engineer, the tract must be 10 acres or larger, every part of the OSSF must sit at least 100 feet from the property line, effluent must stay on the property, and the home must be the only dwelling on the tract⁵. An emergency repair, such as replacing a tank lid or an inlet or outlet device, does not need a permit but must be reported in writing within 72 hours after the repair begins⁵. About 33.3% of McMullen County's soils are free of severe limitations for a conventional septic drain field, better odds than many rural Texas counties, but still worth a site evaluation before you buy¹².

Because McMullen County has adopted no zoning, no county zoning rule restricts RV occupancy, tiny-home occupancy, temporary camping or accessory dwellings on private unincorporated land³. The state camping prohibition applies to public places, not private land¹³. One statewide rule still applies: an uninstalled manufactured home may not be occupied for any purpose other than viewing it on a retailer's sales lot, so a manufactured home has to be installed on its site before anyone lives in it¹⁴. Any home still needs a lawful septic system⁵, and a manufactured home within, partially within, or adjacent to a mapped flood hazard area needs a floodplain development permit from the County Judge's office before placement^9,10.

1. Check whether your parcel sits in a mapped flood hazard area using the FEMA floodplain maps on the county's website; if it does, file a floodplain development permit with the County Judge's office before you build^2,9.
2. Apply for an OSSF (septic) permit through the county's OSSF program before installing a system, unless your tract qualifies for the state's 10-acre exemption^4,5.
3. If you will drill or expand a well, check the McMullen Groundwater Conservation District's rules: a well expected to produce more than 25,000 gallons a day needs a district permit with a $100 application fee, while smaller exempt wells must still be registered⁷.
4. If your driveway will connect to a state highway or farm-to-market road, submit TxDOT Form 1058 and give TxDOT 24-hour notice before construction begins on the right of way^8,15.
5. Because McMullen County has adopted no zoning, there is no county setback, lot-size or building-height review to clear; if you are splitting a tract, check the county Subdivision Regulations first^3,6.

McMullen County averages 24.7 inches of rain a year and has spent roughly 16.3% of years in severe drought, so confirm well capacity or another water source before closing¹². About 33.3% of the county's soils are free of severe septic limitations, and all of the county's land sits at 15% slope or less, so terrain rarely limits building here -- soil type and depth to groundwater matter more¹². Federal land covers only 1.5% of the county, so most of McMullen County is private -- confirm mineral and surface ownership separately, since this is active oil and gas country¹². The county's effective property tax rate is about 2%, with a median property tax bill of $2,167 a year¹². McMullen County sits roughly 73 miles from the nearest metro area, with a population density of 0.5 people per square mile, so plan on long drives for services, hardware and emergency response¹².