Off-grid site report
Bexar County, TX
29.3268, -98.5988 · 630 ft elevationRead this before you act on anything below. This is my researched starting point for Bexar 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 rulesBexar County, TX
Zoning & raw-land occupancy
Varies locallyBexar County has no zoning authority in unincorporated areas, per the county's own FAQ. But if your land is within San Antonio's or Helotes' Extraterritorial Jurisdiction (ETJ), that city can impose land-use requirements under state law.
Dwellings, tiny homes & RVs
Generally allowedSingle-family dwellings, including tiny homes, generally don't need a county residential building permit in unincorporated Bexar County; only commercial, public-access, or multi-family (3+ unit) structures trigger county permit review. Whether Commissioners Court restricts mobile/manufactured homes specifically is not confirmed, ask the Fire Marshal's Office. source
Building permits & codes
Varies locallyPermits are required in unincorporated areas only for commercial, public-access, or multi-family construction, determined by the Bexar County Fire Marshal's Office. If your land is inside a city or its ETJ, that municipality's building code applies as well. source
Septic & composting toilets
Generally allowedBexar County Environmental Services Department requires a permit for all on-site sewage facilities (OSSF) countywide, following state OSSF rules. Composting toilets aren't separately addressed, so treat them as falling under the same OSSF review until confirmed with the department.
Greywater reuse
Unclear - verifyNo standalone Bexar County greywater rule was found; it's presumably handled through the same OSSF permitting process as septic. Confirm specifics with Bexar County Environmental Services.
Rainwater harvesting
Unclear - verifyNo Bexar County-specific page on rainwater harvesting permitting was found. The state's generally permissive baseline likely applies, but this isn't confirmed at the county level.
Private wells & water rights
RestrictedAll wells in Bexar County fall under the Edwards Aquifer Authority, a special groundwater district; even small exempt domestic wells must be registered and meet construction standards, though they don't need a volumetric withdrawal permit.
Living disconnected from utilities
Varies locallyThere's no explicit county mandate to connect to grid utilities, but CPS Energy electrical service for a new residence using an OSSF is gated behind septic system approval by Bexar County Environmental Services.
Sun30-year normals
- Peak-sun hours, annual average
- 5.4 hrs/day
- Worst month (sizes an off-grid array)
- 4.2 hrs/day
- Yearly output per 1 kW of panels
- 1,502 kWh
JFMAMJJASOND
Weather1991-2020
- Precipitation
- 31 in/yr
- Heating degree days
- 1,410 (mild)
- Frost-free season
- Feb 24 to Nov 30
How far help isstraight-line
- Hospital
The Children's Hospital of San Antonio - 9.2 mi
- Fire station
San Antonio Fire Station 4 - 10.3 mi
- Hardware store
The Home Depot - 7.9 mi
- Grocery
H-E-B plus! - 4.6 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 78242).
Size a solar systemHeat loss & insulationFirewood per winterRainwater harvestGarden sizePanel tilt
Looking at a specific parcel in Bexar 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.