Texas
Buying Land in Frio County, Texas
Frio County, seat Pearsall, is South Texas agricultural and ranch country on the I-35 corridor toward Laredo, layered with real Eagle Ford Shale oil-and-gas activity. Here's what's genuinely local: the regional groundwater district, a named sour-gas field worth knowing about, and how septic permitting actually works here.
The land and agricultural economy
Frio County's land market reflects a long agricultural history: the county was, by 1982 figures, the largest peanut producer in Texas (over 50 million pounds that year) and the state's top watermelon producer the same year, alongside potatoes, spinach, cucumbers, beef cattle, and goats. Pearsall's "World's Largest Peanut" roadside monument is a direct, still-standing marker of that history. Today, agriculture continues alongside oilfield services and hunting leases as named, current elements of the local economy -- a South Texas brush-country hunting-lease market is a real and active part of what land here is bought and used for, not a marginal footnote.
Water: the Evergreen Underground Water Conservation District
Groundwater in Frio County is managed by the Evergreen Underground Water Conservation District, covering Atascosa, Frio, Karnes, and Wilson Counties and participating in regional planning through Groundwater Management Area 13. With agricultural use reported at roughly 76% of the district's groundwater production, well-permitting priorities here lean toward irrigation demand more than a district built primarily around municipal supply. Confirm current well-permit requirements, exemption thresholds, and any spacing rules directly with Evergreen UWCD before drilling a new well.
Eagle Ford Shale: real activity, and a named sour-gas field to know about
Frio County is part of the Eagle Ford Shale play that runs roughly 400 miles across South and East Texas, and while drilling has historically been more concentrated in neighboring Atascosa, Dimmit, La Salle, McMullen, and Zavala Counties, named operators including Blackbrush Oil & Gas, Cabot Oil & Gas, and US Enercorp have active operations in Frio County itself. Worth knowing specifically: the Eagleville field, identified by the Railroad Commission as "Eagle Ford Sour," is located in Frio County and is one of a limited number of Texas fields flagged for hydrogen sulfide (H2S) content -- a genuine, checkable safety consideration distinct from ordinary oil-and-gas surface-use questions. Under Texas law, a mineral-rights holder or lessee generally has the right to use as much of the surface as reasonably necessary to explore, drill, and produce, and that right of ingress and egress cannot simply be denied by the surface owner -- though it doesn't obligate the operator to use existing roads, and many operators now drill horizontally from an off-site location to reach minerals beneath a location where a surface pad isn't practical or wanted. Before buying land here, especially near known Eagle Ford activity, have a Texas oil-and-gas attorney review the mineral-rights and surface-use status of a specific parcel, and ask the Railroad Commission directly whether H2S contingency-plan requirements apply to that area.
Septic and subdivision: confirm current process directly
Frio County maintains its own posted OSSF (septic) permit application and Subdivision Regulations document, administered through the county's engineering and health functions. This research found septic-related staffing tied to the Texas Department of State Health Services' regional Public Health Region 8 office rather than a clearly separate, dedicated county environmental health department, so this research could not fully confirm whether Frio County holds TCEQ authorized-agent status outright or whether permitting is effectively handled through that regional structure. Confirm current OSSF fees, site-evaluation requirements, and subdivision/platting rules directly with the county (830-334-4104) before budgeting a septic system or planning a land split.
Who to Call Before Buying Land in Frio County
Frio County has no general zoning ordinance for its unincorporated area, consistent with the statewide default -- there is no planning_zoning entry above because land-use control here runs through subdivision platting rather than zoning. For a mineral-rights or oil-and-gas surface-use question, contact the Texas Railroad Commission directly rather than the county.
Subdivision & Land Development
Frio County Engineer
Subdivision plat review and Subdivision Regulations questions for unincorporated Frio County land.
Septic / Onsite Wastewater
Frio County OSSF Program / Public Health Region 8
Septic (OSSF) permit applications and inspections for unincorporated Frio County land -- confirm current authorized-agent status directly.
Wells / Private Water
Evergreen Underground Water Conservation District
Well permits, registration, and production rules for any well in Frio, Atascosa, Karnes, or Wilson County.
Assessor / Property Tax
Frio County Appraisal District
Assessed value, property tax, and agricultural (1-d-1 open-space) valuation applications for a specific parcel.
Recorder / Clerk / Land Records
Frio County Clerk
Recorded deeds, mineral leases, and easement history for a specific parcel.
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Get local guidanceSources
- Evergreen UWCD — Texas Alliance of Groundwater Districts (accessed 2026-09)
- District Overview — Evergreen Underground Water Conservation District (accessed 2026-09)
- Eagle Ford Shale Drilling Permits In Frio County, TX — ShaleExperts (accessed 2026-09)
- Eagle Ford FAQs — Railroad Commission of Texas (accessed 2026-09)
- Frio County: History, Geography, and Economy — Texas State Historical Association (accessed 2026-09)
- Septic System Permit — Frio County, Texas Government (accessed 2026-09)
- Subdivision Regulations — Frio County, Texas Government (accessed 2026-09)
- Frio County Appraisal District — Frio County Appraisal District (accessed 2026-09)
Last reviewed 2026-09