Off-grid site report
Castro County, TX
34.5503, -102.3118 · 3,898 ft elevationRead this before you act on anything below. This is my researched starting point for Castro County, TX, not legal advice and not a guarantee. Rules change, and the deciding facts on any specific parcel (setbacks, perc results, overlay districts, deed restrictions, road frontage) live at the county or town office, not in any database. Before you buy land or build, confirm the current rules directly with the local zoning and health offices - the sources on this page tell you exactly who to call.
The local rulesCastro County, TX
Zoning & raw-land occupancy
Unclear - verifyNo countywide zoning ordinance or planning department was found on Castro County's official site; Texas counties generally lack broad zoning power over unincorporated land, so state baseline likely applies. Incorporated towns like Dimmitt may have their own zoning. source
Dwellings, tiny homes & RVs
Unclear - verifyNo Castro County rule on minimum dwelling size, tiny homes, or RV occupancy was found; not confirmed whether the county has exercised its narrow state-granted authority to regulate residential construction.
Building permits & codes
Unclear - verifyNo adopted building code or building permit office was found for Castro County; Texas does not require counties to adopt a code, so unincorporated areas may have none, unlike incorporated towns. source
Septic & composting toilets
Generally allowedTCEQ regulates septic systems (OSSFs) statewide under Texas Health and Safety Code Chapter 366 and 30 TAC Chapter 285, requiring a permit; it's not confirmed whether Castro County or TCEQ's regional office administers permitting locally. A 10+ acre exemption may apply for a single dwelling meeting setback and nuisance conditions. source
Greywater reuse
Unclear - verifyNo standalone greywater rule was found at the county or state level; it's generally handled within the same OSSF/septic framework TCEQ oversees.
Rainwater harvesting
Generally allowedNo Castro County restriction on rainwater harvesting was found, and Texas state policy through the Texas Water Development Board encourages it for domestic use.
Private wells & water rights
Varies locallyWell regulation depends on whether the parcel sits inside a Groundwater Conservation District; Castro County's GCD status was not confirmed in this research, though it overlies the historically overdrafted Ogallala Aquifer, so check the TWDB district finder before drilling. source
Living disconnected from utilities
Unclear - verifyNo state or Castro County rule requiring utility hookup was found; any such requirement would likely come from an incorporated town rather than the county.
Sun30-year normals
- Peak-sun hours, annual average
- 6.3 hrs/day
- Worst month (sizes an off-grid array)
- 5.0 hrs/day
- Yearly output per 1 kW of panels
- 1,763 kWh
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Weather1991-2020
- Precipitation
- 21 in/yr
- Snowfall
- 12 in/yr
- Heating degree days
- 4,441 (moderate)
- Frost-free season
- Apr 23 to Oct 20
How far help isstraight-line
- Hospital
Plains Memorial Hospital - 0.5 mi
- Fire station
- none within range
- Hardware store
Kendrick Oil Co - 23.9 mi
- Grocery
Walmart Supercenter - 20.7 mi
From OpenStreetMap. Road miles will be longer, often much longer in hill country.
Plan this spot
These open with this location's real numbers already filled in (ZIP 79027).
Size a solar systemHeat loss & insulationFirewood per winterRainwater harvestGarden sizePanel tilt
Looking at a specific parcel in Castro County, TX?The rules above are the jurisdiction. The land check runs the parcel itself: flood zone, soils and septic suitability, wetlands, slope, access, climate, and these verdicts, from a parcel number or coordinates.
Check a parcel →Share or save this report:New report
Sources: US Census Bureau geocoder; NLR PVWatts v8 (solar); NOAA NCEI 1991-2020 climate normals (nearest station) or Open-Meteo (ZIP-centroid) for weather; Open-Elevation; OpenStreetMap contributors. Public data retrieved Aug 21, 2026; agencies update their layers on their own schedules. Planning data, not a survey or legal advice.
New here, or not sure where this fits? Start here walks through the whole thing in order.