Building permits, zoning and land rules in Castro County, Texas

An ordinary home on unincorporated land in Castro County generally does not require a county building permit¹. The important unresolved point is inspections: Texas law allows a qualifying county to adopt residential construction standards by resolution or order, but we could not confirm whether Castro County has adopted that program². If adopted, new construction on a vacant lot requires foundation, framing-and-systems, and completion inspections performed by an authorized inspector². Ask the County Judge's office whether a current Chapter 233 order applies to the parcel and project before construction begins^2,8. Industrialized or modular housing follows a separate state program, including state codes and an installation-permit option for a buyer acquiring a unit for personal use^9,10.

Castro County does not list a dedicated building department in the available county information, so start with the Castro County Judge at 100 East Bedford, Room 111, Dimmitt, Texas 79027, or 806-647-4451⁸. Ask whether the Commissioners Court has adopted a Chapter 233 residential-inspection order, whether the project needs any county notice, and which precinct commissioner handles access from a county road². TCEQ Region 1 in Amarillo handles the septic path where no local authorized agent has been designated⁵. The High Plains Underground Water Conservation District handles well permitting only in the portion of Castro County inside its boundaries⁷. A driveway connecting to a Texas state highway goes through the local TxDOT district rather than the county¹¹.

Unincorporated Castro County has no general county zoning authority, so county zoning does not set minimum dwelling size, minimum lot size, setbacks, lot coverage, building height, zoning districts, or occupancy rules for RVs, tiny homes, manufactured homes, accessory dwellings, and temporary camping³. That answer is limited to county zoning on unincorporated land; private deed restrictions can still affect a parcel. Inside Dimmitt, the city publishes a zoning map and a code-inspector fee schedule for building permits, so a lot within city limits follows city rules rather than this county answer^4,12. Septic permits for a Dimmitt address still come through the septic route described below, not the city⁵. We could not confirm the rules of the county's other incorporated places, so ask the city directly. Lack of county zoning also does not remove septic requirements, the conditional state inspection framework, the industrialized-housing program, or state-highway driveway rules^2,5,9,11.

TCEQ Region 1 in Amarillo is the septic contact for Castro County where no local authorized agent operates⁵. A permit and approved plan are normally required to construct, install, alter, extend, repair, or operate an on-site sewage facility, and the permitting authority has 30 days after receiving the application and planning materials to approve or deny them⁵. A single-family home on at least 10 acres may qualify for an exemption only when every state condition is satisfied, including a professional site evaluation, at least 100 feet between every system component and the property line, on-property effluent disposal, no nuisance or groundwater pollution, and no other dwelling on the tract⁵. Only about 19.4% of county soils avoid a severe conventional-drain-field limitation, so treat soil evaluation as an early feasibility step rather than assuming a standard field will work¹³.

County zoning does not restrict RV occupancy, tiny-home occupancy, manufactured-home occupancy, accessory dwellings, or temporary camping on unincorporated land in Castro County³. That does not make every setup permit-free: wastewater disposal remains subject to Texas OSSF rules, and industrialized or modular units can fall under the state industrialized-housing program^5,9. Inside an incorporated city, ask the city about zoning, utility connections, placement standards, and occupancy because the county answer does not control municipal land. For an off-grid setup, confirm the sanitation design with TCEQ Region 1 before buying equipment; we could not confirm a separate Castro County rule for composting toilets, holding tanks, or other alternative sanitation systems¹⁴.

1. Ask the County Judge's office whether a Chapter 233 residential-inspection order, county-road access requirement, or floodplain process applies to the parcel^2,8.
2. Confirm whether the tract lies inside High Plains Underground Water Conservation District territory; smaller wells can be permit-exempt there but may still need registration⁷.
3. Have the site evaluated for wastewater and apply through TCEQ Region 1 unless every condition of the state septic exemption is met^5,14.
4. If access connects to a state highway, submit the required driveway application and wait for a fully executed TxDOT permit before work in the right of way¹¹.
5. Owner-builders should verify trade licensing separately: state exemptions can cover an owner's electrical, plumbing, or air-conditioning work on the owner's residence or homestead, but they are not a blanket exemption from every contractor rule⁶.

Start with water and septic feasibility. Castro County receives about 19.3 inches of precipitation annually, and severe drought occurs in about 40.3% of years¹³. Only about 19.4% of soils avoid severe limitations for a conventional septic drain field, so obtain a site evaluation before choosing a house site¹³. The land is broadly flat, with 100% at slopes of 15% or less, but flat ground does not answer drainage or floodplain questions¹³. Castro County participates in the National Flood Insurance Program, but we could not confirm its current flood map status, permit form or fee, so ask the County Judge's office about the specific parcel^8,15. Also confirm legal access and whether the road is county-maintained or a state highway. Farmland value averages about $2,130 per acre, while the effective property-tax rate is about 1.1% and the median annual property-tax bill is about $1,067¹³.