Off-grid site report
Hays County, TX
29.8810, -97.9122 · 587 ft elevationRead this before you act on anything below. This is my researched starting point for Hays 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 rulesHays County, TX
Zoning & raw-land occupancy
Generally allowedHays County confirms it has no general zoning authority in unincorporated areas, with a narrow exception for airport zoning near San Marcos Regional Airport administered by the City of San Marcos. If land is inside a city limit, check that city's zoning instead.
Dwellings, tiny homes & RVs
Varies locallyNo county building code or minimum size rule was found, but the county requires a state-authorized three-stage inspection program for new home construction in unincorporated areas. RVs as permanent dwellings and tiny homes specifically are not addressed in county materials found, so confirm with Development Services. source
Building permits & codes
Varies locallyHays County has no general residential building code, but requires a development permit for all land-disturbing activity, and applies the International Fire Code to multifamily, public, and commercial buildings via the Fire Marshal's Office. source
Septic & composting toilets
Generally allowedSeptic (OSSF) systems are permitted and required countywide under Texas Health and Safety Code Chapter 366 and 30 TAC 285, administered by Hays County; a permit is needed regardless of lot size, and homeowners may self-install. source
Greywater reuse
Unclear - verifyNo standalone Hays County greywater ordinance was found; it appears folded into OSSF/state permitting rules. Not confirmed as its own permit category, so ask Environmental Health directly. source
Rainwater harvesting
Generally allowedHays County and the City of Woodcreek adopted a local property tax exemption for rainwater harvesting under the state's water conservation initiatives law, and the county actively supports rainwater collection. source
Private wells & water rights
Varies locallyWestern Hays County falls under the Hays Trinity Groundwater Conservation District, which requires well notification for all wells and is currently in an emergency drought stage blocking new well permits. Eastern county coverage by a district is not confirmed; state rule of capture likely applies there by default.
Living disconnected from utilities
Generally allowedNo countywide requirement to connect to electric or water utilities was found for single-family homes; TCEQ public water supply rules only apply at 15+ connections or serving 25+ people regularly.
Sun30-year normals
- Peak-sun hours, annual average
- 5.4 hrs/day
- Worst month (sizes an off-grid array)
- 4.3 hrs/day
- Yearly output per 1 kW of panels
- 1,507 kWh
JFMAMJJASOND
Weather1991-2020
- Precipitation
- 36 in/yr
- Snowfall
- 0 in/yr
- Heating degree days
- 1,637 (mild)
How far help isstraight-line
- Hospital
Christus Santa Rosa Hospital - 2.8 mi
- Fire station
Fire Station #1 - 1.8 mi
- Hardware store
Lowe's - 3.0 mi
- Grocery
Walmart Supercenter - 0.2 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 78666).
Size a solar systemHeat loss & insulationFirewood per winterRainwater harvestGarden sizePanel tilt
Looking at a specific parcel in Hays 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.