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

No. Unincorporated Frio County has no general residential building-permit program, and Texas counties are not given broad authority to require one¹. State law grants that power only in narrow situations, such as fire-code permits for large counties and commercial or multifamily buildings, or residential standards a county formally adopts by resolution¹⁰. Whether Frio County has adopted such a resolution is unconfirmed; the Frio County Commissioners Court is the office to ask¹⁰. An ordinary single-family home, cabin, barn or shop in unincorporated Frio County does not appear to go through county building-permit review, though the county does issue the septic permit for the system serving it^1,4. Inside the city of Dilley, ask the city, because city rules differ from the county's³.

There is no county building or zoning office to call for an ordinary home, because Frio County does not run a general building-permit program¹. Septic permits, subdivision plats, utility permits in county rights-of-way and 911 addressing all go through the county's Road & Bridge Department instead⁴. For floodplain development permits, which the county does regulate without listing a dedicated office, the Frio County Courthouse in Pearsall is the general contact¹¹. A driveway onto a TxDOT-maintained highway needs a TxDOT driveway permit before Frio County will issue a 9-1-1 address⁶.

Unincorporated Frio County has no zoning ordinance, and Texas law gives counties zoning authority only for a handful of specific areas that do not include Frio County^1,2. The county itself therefore sets no minimum home or lot size, no setbacks, no building-height limit and no zoning districts². Accessory dwellings, tiny homes and temporary camping on your own unincorporated lot are unrestricted under county rules². The city of Dilley is different: its ordinance page lists a zoning ordinance, so check the City of Dilley before buying inside city limits³. Even there, septic permits still come from the Frio County Road & Bridge Department⁴. County zoning does not exist, but the county does review plats when land is divided into new lots⁴.

Frio County itself, not the state, issues septic permits for on-site sewage facilities (OSSFs), acting as TCEQ's authorized local agent, and the county's subdivision regulations say the County Engineer's office issues permits and inspects all OSSFs⁴. A homeowner may do the work directly on a system serving the homeowner's own single-family residence; paid work must be done by a state-licensed person⁴. The Road & Bridge Department reviews and approves septic applications, with fees set at $200 for a residential system and $450 for a commercial or aerobic system, payable only by money order or cashier's check^4,7. Texas's statewide 10-acre exemption can still apply if a licensed site evaluator signs off, the tract is at least 10 acres with a single dwelling, and every part of the system stays 100 feet from the property line¹². Only 35% of Frio County's soils are rated free of severe limits for a conventional septic drain field, so a site evaluation matters even where the exemption doesn't apply¹³. Frio County sits in the Evergreen Underground Water Conservation District, where a well producing more than 25,000 gallons a day or 17.5 gallons a minute needs a production permit; smaller, exempt wells still must be registered with the district before drilling⁸.

Yes, as far as county rules go. Unincorporated Frio County has no zoning ordinance restricting how you occupy your own land, so there's no county rule limiting RV or tiny-home living, and no minimum home size to meet². A separate county rule only reaches Manufactured Home/Mobile Home/RV Rental Communities: land split into two or more spaces rented or leased for under 60 months without a purchase option, which needs an Infrastructure Development Plan approved by the County Engineer and Commissioners' Court, plus a County Certificate of Compliance before utilities can connect⁹. That rule doesn't reach a single RV, tiny home or manufactured home on your own lot outside a rental community⁹. Whatever you live in, remember it still needs a compliant OSSF permit if it has plumbing¹².

First, order a site and soil evaluation for your septic system early, since only 35% of the county's soils are free of severe limitations for a conventional drain field¹³. Second, apply for your OSSF permit through the Frio County Road & Bridge Department, paying $200 for a residential system or $450 for a commercial or aerobic system, by money order or cashier's check^4,7. Third, if you need a well beyond the district's exempt-well threshold, apply for a production permit through the Evergreen Underground Water Conservation District; even an exempt well must be registered before drilling⁸. Fourth, if your property is in a mapped Special Flood Hazard Area, get a Floodplain Development Permit before you start work; it's valid for one year and must be renewed if the work isn't finished⁵. Fifth, if your driveway connects to a TxDOT-maintained highway, get a TxDOT driveway permit first, since Frio County won't issue a 9-1-1 address without one⁶. Sixth, if you're creating a new lot rather than buying an existing one, check with the Road & Bridge Department on subdivision plat requirements⁴. Finally, build: there is no countywide building-permit review for an ordinary single-family home outside a floodplain¹.

Water and drought deserve real attention here: annual precipitation runs about 24.2 inches a year, with severe drought in 30.7% of years, and any well beyond the Evergreen district's exempt-well threshold needs a production permit^8,13. Septic soils are better than in many counties on this site, with 35% of the land free of severe limitations for a conventional drain field, though a site evaluation is still worth doing before you commit¹³. Land here is essentially flat, with 100% at 15% slope or less and only 16.1% forested, so clearing costs are usually modest¹³. Check FEMA flood maps before you buy: development in a mapped Special Flood Hazard Area needs a county Floodplain Development Permit⁵. If the tract fronts a TxDOT-maintained highway, budget for a TxDOT driveway permit, since the county won't assign a 9-1-1 address without one⁶. Property tax runs about 1.6% effectively, with a median bill near $1,751 a year, against a typical home value around $173,743¹³.