The TCEQ OSSF permit process, explained plainly.

If you are installing, replacing, or significantly altering a septic system on property in Texas that is not connected to a public sewer, you are operating in the OSSF regulatory space. Understanding how that space works is the difference between a smooth permit and a project that stalls at the county office for three months.

What OSSF means

OSSF stands for On-Site Sewage Facility. It is the Texas regulatory term for any system that treats and disperses wastewater on the same property that generates it. Septic tanks, aerobic treatment units, drip irrigation systems, and mound systems all fall under the OSSF umbrella.

The Texas Commission on Environmental Quality (TCEQ) writes the rules that govern OSSF systems statewide under Title 30, Chapter 285 of the Texas Administrative Code. Individual counties administer the permit process under an authorized agent agreement with TCEQ. This is why you apply to your county rather than to TCEQ directly, but the underlying rules are the same statewide.

When you need an OSSF permit

Texas law requires an OSSF permit for any of the following:

• Installing a new septic system on a property not connected to public sewer
• Replacing an existing system with a new system (not just pumping or routine maintenance)
• Modifying an existing system in a way that changes its design, capacity, or location
• Repairing a failed system (though some repair work falls under separate repair authorization rules)
• Adding a bedroom or other significant habitable square footage to a home that changes the required system capacity

Routine maintenance, tank pumping, and minor repairs to an existing functioning system generally do not require a full OSSF permit. If you are unsure whether your work triggers the permit requirement, contact the OSSF department at your county or ask a TCEQ-licensed professional.

The soil and site evaluation: the foundation of the permit

Before any permit application is filed, the land must be evaluated to determine whether and how it can support an OSSF system. This is not optional and it is not interchangeable with a generic soil report. The evaluation must be conducted by a TCEQ-authorized site evaluator.

What the evaluation covers

The site evaluator digs or bores into the soil at multiple locations across the proposed drainfield area. They document the soil profile: texture (sand, silt, clay), structure (granular, blocky, platy), color (used to identify redoximorphic features indicating seasonal saturation), and the depth to restrictive layers (rock, caliche, or seasonally saturated zones).

Based on the soil profile, the evaluator determines the long-term acceptance rate (LTAR) for the site — essentially how many gallons per square foot per day the soil can absorb without surfacing or backing up. The LTAR drives the minimum drainfield square footage required for the design.

Perc testing vs. soil morphology

Texas allows two methods of site evaluation: traditional percolation testing (perc tests) and soil morphology analysis. Soil morphology — evaluating soil structure, color, and profile characteristics rather than conducting timed water infiltration tests — is now the preferred method under current TCEQ rules. It is faster, more reliable, and does not require saturating the soil before testing. Not all evaluators are equally proficient at soil morphology interpretation, particularly on the complex geology of the Hill Country.

Evaluation limitations and what can change the result

Evaluations reflect conditions at the time of the evaluation. Seasonal variation in water table depth, drought conditions, or recent excavation work can affect results. If a site evaluation comes back with limiting conditions, it does not necessarily mean the project is dead; it may mean that a different system type (aerobic, mound, drip irrigation) is required rather than a standard gravity drainfield.

The permit application process, step by step

Once the site evaluation is complete, the permit process moves through these stages. The licensed designer typically manages the paperwork; the homeowner’s job is to supply accurate property information and respond quickly when the county requests additional documentation.

Step 1: Design

Using the soil evaluation data, a TCEQ-licensed designer prepares a site plan showing the location of the tank, distribution system, and drainfield. The design must comply with all setback requirements from property lines, water wells, surface water, drainage easements, and structures. The design is drawn to scale and submitted with the permit application.

Step 2: Permit application to the county

The application goes to the county’s OSSF permitting authority (typically the County Environmental Health department or a delegated local authority). The application package includes the site plan, soil evaluation data, property survey or plat, and the permit fee. Travis County’s fee is approximately $700; Hays County is in a comparable range. Fees and required documents vary by county; confirm current requirements directly with your county before submitting.

Step 3: Application review

The county authorized agent reviews the application for completeness and code compliance. This step can take anywhere from a few days to a few weeks depending on the county’s workload and whether the application is complete on first submission. Incomplete applications are returned with a list of deficiencies. A designer who has worked regularly with your county can anticipate what reviewers look for and reduce back-and-forth.

Step 4: Permit issuance and installation authorization

Once approved, the county issues the OSSF permit. Work cannot legally begin before the permit is in hand. The permit specifies the approved design, approved materials, and any special conditions. It also initiates the inspection schedule.

Step 5: Installation and inspections

Installation proceeds according to the approved design. The county typically requires inspections at two points: before the system is covered (to verify installation matches the design) and after final grading and any electrical or irrigation components are complete. The inspector is a county-authorized OSSF inspector, not a building inspector.

If the installation deviates from the approved design, the county may require corrections before the system is covered. This is why having the same licensed professional manage both the design and the installation matters: any field adjustment is documented, authorized, and consistent with the approved permit rather than improvised after the fact.

Step 6: Final approval and documentation

After passing all inspections, the county issues a final approval and updates the OSSF permit record. This documentation follows the property and becomes part of its title history. It is the official record that a code-compliant, permitted system exists on the property — which matters if you sell, refinance, or need to add a structure.

County differences that matter

TCEQ sets the floor for OSSF rules, but counties can adopt rules that are more stringent than the state minimum. In practice, this means permit fees, required documents, inspection timing, and specific design standards can differ across Travis, Hays, Bastrop, Caldwell, and Blanco counties.

Travis County and Hays County are among the more active OSSF jurisdictions in Central Texas, with well-staffed offices and established processes. For property in Austin’s extraterritorial jurisdiction or unincorporated Travis County, the permit goes through Travis County Environmental Health. For Buda, Kyle, Wimberley, and Dripping Springs properties outside city limits, the application goes to Hays County Environmental Health.

For county-specific detail, see the Travis County septic permit guide and the Hays County septic permit guide.

Common reasons permit applications are delayed or denied

• Incomplete soil evaluation. Missing borings, insufficient depth documentation, or evaluations conducted by an unauthorized person.
• Setback violations in the design. Drainfield too close to a water well, property line, or surface water body.
• Missing property survey or legal description. The county needs to place the system on a legally described parcel.
• Unlicensed designer. The design must be sealed or signed by a TCEQ-licensed OSSF designer. An unlicensed contractor’s sketch is not acceptable.
• System type not suited to site conditions. Proposing a conventional gravity system on a site with limiting soil conditions that require an aerobic or alternative design.

Aerobic systems: additional regulatory requirements

Aerobic treatment units are subject to additional oversight beyond the standard OSSF permit. Texas requires that every installed aerobic system have an active maintenance contract with a licensed maintenance company. The maintenance provider must inspect the system at least four times per year, document performance and chlorine or disinfection tablet levels, and report to the county. Failure to maintain an active maintenance contract puts the property owner in violation of state law.

When evaluating an aerobic system installation, confirm that your installer can connect you with a maintenance provider before the permit closes. Some installers also provide maintenance services; others work with dedicated maintenance contractors. Either arrangement is acceptable as long as the licensed provider is documented with the county.

After the permit: keeping your records

Keep a copy of your OSSF permit, the approved site plan, and all inspection reports in your home records. These documents are needed when selling the property, applying for certain building permits, and when troubleshooting a system problem years later. The county maintains records, but your copy is your fastest path to accurate information when you need it.