When Hill Country homeowners research septic regulations, most find the Texas Commission on Environmental Quality (TCEQ) and stop there. That’s a reasonable starting point — but it’s not the finish line. County septic rules in Texas operate on top of state standards, and in many Hill Country counties, those local rules are stricter, more specific, and more consequential than anything in the state baseline. A homeowner who knows 30 TAC Chapter 285 cold but hasn’t verified what their county requires is only halfway informed.
This guide explains how county septic rules in Texas work, why they vary across the Hill Country, and what homeowners need to confirm at the local level before any OSSF installation, repair, or modification.
How County Septic Rules in Texas Differ From State Standards
The TCEQ administers Texas’s on-site sewage facility program under 30 TAC Chapter 285. That rule establishes the statewide minimum standards — setback distances, soil requirements, system design criteria, maintenance obligations, and permitting procedures. Every OSSF in Texas must meet those minimums.
What 30 TAC Chapter 285 also does is authorize counties and municipalities to become the local permitting authority for OSSFs within their jurisdiction. These entities — called authorized agents — take on responsibility for permitting, inspection, and enforcement in their area. And critically, authorized agents are permitted to adopt rules that are more stringent than the state minimum. They cannot go below the TCEQ floor. They can go above it.
County septic rules in Texas, therefore, reflect a layered system: state minimums at the foundation, county requirements built on top. A homeowner in Kendall County and a homeowner in Kimble County are both subject to 30 TAC Chapter 285 — but they may face meaningfully different local requirements on top of that shared baseline.
Why Hill Country Counties Go Further Than State Minimums
The Hill Country’s geology and hydrology give counties strong reasons to adopt stricter local standards. Karst limestone, shallow soil depth, fractured bedrock, and proximity to the Edwards Aquifer recharge zone create contamination pathways that flat, sandy-soil counties don’t face to the same degree. A failing OSSF in deep East Texas loam poses a different risk profile than a failing system in thin Kerr County limestone soil above a fractured aquifer.
Several Hill Country counties have responded to that reality with local rules that go beyond state minimums — tighter setback requirements, more restrictive soil evaluation standards, additional inspection requirements, or specific system type restrictions in sensitive areas. The Edwards Aquifer recharge zone, which underlies portions of several Hill Country counties, triggers an additional regulatory layer coordinated between county programs, the TCEQ, and the Edwards Aquifer Authority.
The Hill Country County Landscape
County septic rules in Texas vary enough across the Hill Country that homeowners should treat each county as its own regulatory environment. Here is a county-by-county overview of the authorized agent structure across the primary Hill Country counties.
Kerr County. Kerr County operates its own authorized OSSF program through the county’s environmental health office. Homeowners in Kerrville, Ingram, Hunt, Center Point, and surrounding unincorporated areas apply for permits through the county. Following the July 2025 floods, Kerr County’s OSSF program has been actively engaged in post-disaster system assessments across affected areas.
Gillespie County. Gillespie County is an authorized agent with its own OSSF permitting program. Fredericksburg and surrounding rural areas fall under county jurisdiction. Gillespie County’s program reflects the region’s agricultural character and the prevalence of both conventional and aerobic systems across the county’s varied terrain.
Kendall County. Kendall County administers its own authorized OSSF program. Boerne and the surrounding Hill Country communities — one of the fastest-growing areas in Texas — have seen significant OSSF permitting activity as rural properties transition to residential development. Kendall County’s program has kept pace with that growth, and its standards reflect both state requirements and local conditions in the Guadalupe River corridor.
Bandera County. Bandera County operates an authorized OSSF program covering Bandera, Medina, and surrounding rural areas. The county’s terrain — cedar-covered hills, thin soils, and creek drainage systems — presents similar geological challenges to Kerr and Gillespie counties.
Blanco County. Blanco County administers its own OSSF permitting program. Johnson City and the surrounding rural areas, including portions of the Pedernales River watershed, fall under county jurisdiction. Blanco County’s proximity to the Edwards Aquifer recharge zone influences local OSSF standards.
Llano County. Llano County operates an authorized OSSF program covering Llano, Kingsland, and surrounding areas including the Llano River corridor. The granite and metamorphic geology of the Llano Uplift — different from the limestone geology of counties to the south and east — influences soil evaluation requirements in this county.
Real, Edwards, Kimble, and Mason Counties. These less densely populated Hill Country counties operate authorized OSSF programs scaled to their smaller populations. Leakey, Camp Wood, Junction, and Mason are the primary permitting centers in these counties. Homeowners in these areas should expect longer permitting timelines due to smaller program staff, and should initiate permit applications well in advance of planned construction or repair.
Burnet, San Saba, Lampasas, and McCulloch Counties. The outer ring of Hill Country counties — covering Burnet, Marble Falls, Horseshoe Bay, San Saba, Lampasas, Brady, and Menard — each operate their own authorized OSSF programs. The Highland Lakes area in Burnet County, with its proximity to the Colorado River lakes and significant residential development pressure, has an active permitting program that reflects both growth and environmental sensitivity.
What Homeowners Must Verify at the County Level
Knowing that county septic rules in Texas exist is only useful if you know what to ask. Before any OSSF installation, repair, modification, or property purchase involving a rural septic system, confirm the following directly with your county’s authorized agent.
Whether a permit is required for the specific work planned. The state minimum requires permits for installation and significant repair. Some counties require permits for component replacements that other counties treat as routine maintenance. Do not assume — ask.
Whether the county has adopted setback requirements more stringent than the state minimums. Setback distances from wells, waterways, property lines, and structures vary. A county with tighter setbacks than 30 TAC Chapter 285 requires may affect whether a planned installation is feasible on a specific lot.
Whether the property falls within a special regulatory zone. Edwards Aquifer recharge zone designations, flood plain overlays, and watershed protection areas can trigger additional requirements beyond standard county rules. Confirm your property’s zone status before designing or permitting a system.
Whether the county requires a licensed engineer for system design. Some counties require engineered designs for certain system types or soil conditions. Others accept designs prepared by licensed installers. Knowing this in advance affects both timeline and cost.
What the current permitting timeline looks like. In fast-growing counties like Kendall and Burnet, permitting timelines have extended as application volume increases. In smaller counties, staffing constraints can create delays. Build timeline reality into any construction or purchase schedule.
How to Find Your County’s Permitting Authority
The TCEQ maintains a searchable database of authorized agents — the local permitting authorities for OSSFs across Texas — at www.tceq.texas.gov. Search by county to find your local contact, office hours, and application requirements.
For Hill Country homeowners, the County Contacts resource on this site provides direct contact information for OSSF permitting offices across all 13 primary Hill Country counties — compiled and verified as a starting point for permit inquiries.
The TCEQ also maintains a database of licensed OSSF professionals at www.tceq.texas.gov. A licensed professional familiar with your specific county’s program — its requirements, its inspectors, and its timelines — is one of the most practical resources available when navigating local permitting.
The Layer You Cannot Afford to Skip
County septic rules in Texas are not a bureaucratic technicality. They are the regulatory layer closest to the ground — literally and practically. They reflect local geology, local water resources, and local experience with what happens when systems fail in specific Hill Country conditions.
A homeowner who installs, repairs, or purchases a rural property based solely on state standards — without confirming what the county requires on top of them — is operating with incomplete information. In a region where the difference between compliant and non-compliant can mean the difference between a clean closing and a failed one, that gap is worth closing before it closes a deal instead.
For related reading, see our guides on TCEQ Septic Permit in Texas, Septic System Setback Requirements in Texas, Septic System Violations in Texas, and Limestone Soil Septic Systems in Texas.