Septic in Walker County, TX

Last updated: Mar 21, 2026

Walker County feels a little like country living with a practical edge—shadowed by pines, spread-out yards, and a dependable, neighborly approach to keeping wastewater moving smoothly. If you've spent time in Huntsville or along the county's rural lanes, you know this place wears its practicality on its sleeve—and that includes the way homes handle waste.

Is septic common in Walker County? Should I expect septic if I own or buy a home?

Yes. Septic systems are the norm for many properties here, especially outside city sewer boundaries or in older subdivisions where main lines haven't reached every street. If you own or are buying a home in Walker County, it's reasonable to expect a septic system unless the property is connected to a municipal sewer. When you're evaluating a property, ask for the septic permit date, the system type, tank size, and the most recent service or pumping records. Have a licensed septic contractor inspect the system and locate the tank so you know what you're working with.

Why homes typically use septic systems in Walker County

  • Rural lot sizes and development patterns: Many homes sit on larger lots where municipal sewer isn't practical or economically justified.
  • Cost and logistics of extending sewer: Building and maintaining long sewer mains through wooded or uneven terrain can be expensive and slow.
  • Soil and drainage considerations: Local soils and groundwater conditions often call for on-site treatment tailored to each property.
  • Privacy and reliability: A well-designed on-site system can be a reliable solution for families who value independence and straightforward maintenance.

County growth history and how that has impacted septic coverage

Walker County has long been a rural mix of ranch land, timber, and small communities. In recent decades, growth around Huntsville—driven by SHSU, local employers, and regional development—has brought more homes and subdivisions. That growth has created a patchwork: some areas now have access to city sewer, while many neighborhoods and rural parcels continue to rely on septic. The result is a broad spectrum of systems, with maintenance and proper sizing becoming increasingly important as the county evolves.

High-level explanation (why septic exists here)

In this part of Texas, on-site wastewater treatment makes practical sense for many properties. The combination of dispersed development, varied soils, and delayed or uneven sewer expansion means septic systems remain a sensible, economical, and environmentally responsible solution when designed and maintained properly.

In the pages that follow, you'll find practical, neighborly guidance you can put to work right away.

How Septic Is Regulated in Walker County

Regulatory framework

In Walker County, septic systems (OSSFs) are regulated at the state level by the Texas Commission on Environmental Quality (TCEQ), with local county health offices handling the hands-on permitting, site evaluations, and inspections. The Walker County Health Department (or its Environmental Health unit) administers the local requirements, processes, and inspections required to install, modify, or repair an OSSF. If you live within a city, check whether the city has its own additional rules beyond the county. Official resources:

Permits you need

Most residential OSSFs require a permit before design, construction, or substantial modification. The process typically looks like this:

  • 1. Hire a licensed designer or engineer to prepare OSSF plans and a soil evaluation.
  • 2. Submit the plan, site plan, and soil evaluation to the Walker County Health Department (or your local authority) for review.
  • 3. Pay applicable permit fees and await approval.
  • 4. Schedule required inspections during key milestones (pre-installation, during construction, and final inspection).
  • 5. Obtain final approval and any operating permits before putting the system into use.

Note: If you're buying or selling a home, verify that the property has a valid permit or a transfer inspection on file. Your real estate transaction may trigger an OSSF inspection or documentation requirement.

Inspections and maintenance

Inspections ensure the system is designed and installed correctly and complies with applicable rules. Expect the following:

  • Site evaluation and soil testing as part of the permit review.
  • On-site inspections during installation to verify trenching, septic tank placement, distribution, and final connection.
  • A final inspection and approval before the system is used.

Ongoing maintenance is the homeowner's responsibility. Keep records of pump-outs and service, and follow the operation and maintenance (O&M) plan provided with your system. Some counties require documented maintenance or pump-outs on transfer of property or as part of local programs; check with Walker County for any transfer-specific requirements.

Transfers and selling property

  • Many counties, including Walker County, require disclosure of septic system status and sometimes an inspection as part of a property sale.
  • If a transfer is involved, you may need a transfer inspection or updated OSSF documentation to finalize the sale.

How to get started: practical checklist

  1. Confirm jurisdiction: Is your property in an unincorporated area of Walker County or within a city with its own rules?
  2. Gather key details: property address, proposed changes, existing system type, any prior permits or records.
  3. Contact Walker County Health Department: request guidance on the permit process and required documents.
  4. Engage a licensed designer/installer: obtain plan reviews and soil evaluation results.
  5. Submit the permit package: include plans, site plan, soil evaluation, and required fees.
  6. Schedule inspections: prepare for pre-construction review, during installation checks, and final approval.
  7. Maintain records: keep all permit documentation, inspection reports, and maintenance receipts accessible.

Official resources

Soil, Groundwater & Environmental Factors in Walker County

Local soil characteristics in Walker County

Walker's soils vary from loamy sands to heavier clays, with pockets of limestone bedrock closer to the surface in places. This mix affects how quickly effluent can move through the soil and how a drain field will perform over time. Poorly draining soils (high clay content) may require larger or differently designed systems, while very rapid draining soils can stress a drain field if not properly sized.

Typical Septic System Types in Walker County

Conventional septic systems

Conventional septic systems are by far the most common choice for single-family homes in Walker County. They rely on a buried septic tank to hold solids and scum, then use a soil-based absorption field to treat and disperse the liquid.

  • How it works
    • Wastewater enters a septic tank, where solids settle and scum floats.
    • Clear effluent exits to a perforated pipe in a buried drainfield, where soil microbes finish the treatment.
  • Pros
    • Simple, time-tested design when soils are suitable.
    • Generally lower upfront cost than advanced systems.
  • Cons
    • Requires adequate, well-draining soil and sufficient depth to groundwater.
    • Performance drops with high water tables, heavy clay, or shallow bedrock.
  • Maintenance
    • Pumping every 3–5 years is typical; frequency depends on tank size and usage.

For official guidance on Texas OSSF programs, see TCEQ: https://www.tceq.texas.gov/permitting/ossf

Alternative and advanced treatment systems

If site conditions or usage patterns challenge a conventional drainfield, alternative or advanced systems can provide higher treatment levels and more design flexibility.

  • Aerobic Treatment Units (ATUs)
    • Use oxygen to boost bacteria activity, producing a higher-quality effluent.
    • Require electricity and regular service.
  • Sand filter and other media filtration systems
    • Pre-treat effluent in a controlled media bed before it reaches the drainfield.
    • Helpful in soils with limited absorption or higher loading.
  • Pros and cons
    • Pros: better treatment in difficult soils, adaptable to tighter sites.
    • Cons: higher initial cost, ongoing maintenance and monitoring.
  • Maintenance
    • Regular service checks, annual pumping when indicated, and follow-up per local requirements.

EPA septic systems overview: https://www.epa.gov/septic

Mound systems

When native soil conditions aren't suitable for a conventional drainfield, a mound system can be raised above the ground surface to provide adequate space for treatment and absorption.

  • How it works
    • An engineered fill creates a raised bed with a drainfield beneath.
  • Pros
    • Enables treatment where depth to groundwater or poor soils would otherwise prevent a system.
  • Cons
    • Higher installation cost and more complex maintenance.
  • Maintenance
    • Routine inspections, proper landscape protection, and adherence to maintenance schedules.

Drip irrigation and evapotranspiration (ET) systems

These options move effluent more gradually into the landscape or rely on plant uptake and evaporation.

  • Drip irrigation
    • Treated effluent is delivered through low-pressure lines to designated landscape zones.
  • ET beds
    • Use evapotranspiration to remove water from the bed.
  • Pros
    • Landscape-friendly and space-efficient; can reduce evapotranspiration load on the drainfield.
  • Cons
    • Requires careful design to avoid root intrusion, clogging, or misapplication.
  • Maintenance

Shared or cluster septic systems

In some rural areas or planned developments, a single larger system serves multiple homes with a common drainfield.

  • Pros
    • Can lower per-home cost and reduce land disturbance.
  • Cons
    • Requires clear governance, maintenance funding, and reliable management.
  • Maintenance
    • Routine inspections and coordinated upkeep per the agreed plan.

Quick site evaluation steps

  1. Check soil depth, percolation, and groundwater near the proposed drain area.
  2. Confirm local permits and any HOA or county requirements.
  3. Schedule a site visit with a licensed OSSF professional or the local health department and reference official guidelines.

Links to official resources:

Typical Septic Issues Across Walker County

Common problems homeowners see

  • Slow drains and backups in sinks, tubs, and toilets.
  • Bad odors or a noticeable sewer smell around the house or drain field.
  • Gurgling sounds in plumbing when a fixture is used.
  • Wet, soggy spots or standing water over the drain field after rain.
  • Unusually lush, green patches or spongy soil over the septic field.
  • Backups or effluent surfacing after heavy water use (laundry, showers, or irrigation).
  • Access lids that are bulging, rusted, or leaking.

Typical causes in Walker County soils

  • High water table or clay-heavy soils limiting absorption in the drain field.
  • Tree roots invading septic lines or the absorption area.
  • Excess solids buildup in the tank from infrequent pumping.
  • Overuse of water fixtures and appliances causing hydraulic overload.
  • Improper disposal of fats, oils, grease, household chemicals, or non-biodegradable items.
  • Cracked or damaged septic tank or distribution lines allowing effluent to surface.

Quick checks you can safely perform

  • Observe for pooling water or damp soil near the drain field after 24–48 hours of normal use.
  • Smell nearby areas for sewer odors, especially near vents, lids, or discharge points.
  • Notice if multiple fixtures drain slowly or back up at once.
  • Look for lush vegetation or unusually green grass directly above the drain field.
  • Inspect for cracks, leaks, or unusual dampness around the septic tank access lids.

Quick troubleshooting steps (safe, non-invasive)

  1. Reduce water use for 24–48 hours to ease pressure on the system.
  2. Avoid chemical drain cleaners; use mechanical plunging for minor clogs and consider professional help for persistent issues.
  3. Check roof vent stacks for blockages (unsupported or blocked vents can increase gurgling and slow drainage).
  4. Keep irrigation and sump pump discharge away from the drain field to prevent oversaturation.
  5. If backups continue, document symptoms (dates, which fixtures are affected) to share with a technician.

Preventive practices that save money and headaches

  • Spread out laundry loads and avoid running many high-water-use appliances simultaneously.
  • Never flush fats, oils, grease, or non-biodegradable items; only toilet paper and waste.
  • Use septic-friendly products and avoid caustic cleaners that can disrupt natural bacteria.
  • Schedule regular inspections and pumping based on household size and system age:
    • Typical schedule: every 3–5 years for a family, more often with heavy usage or aging systems.
  • Protect the drain field:
    • Do not drive or park over the drain field.
    • Plant only shallow-rooted grasses; avoid trees and large shrubs nearby.
    • Keep soil adequately aerated and free of heavy equipment.

When to call a licensed septic professional

  • Persistent backups, foul odors, or wet areas on the drain field after troubleshooting.
  • Visible cracks, exposed pipes, or standing water near the tank or lines.
  • Recurrent issues despite following preventive steps.
  • For inspections, pumping, and repairs, hire a licensed septic contractor. They can perform a tank pump, drain-field evaluation, and camera inspections if needed. See the Texas Commission on Environmental Quality (TCEQ) Onsite Sewage Facilities program for guidance and requirements:
  • Additional official FAQs and consumer-focused information about maintenance and setbacks: https://www.epa.gov/septic

Septic Inspection, Permits & Local Oversight

Local oversight in Walker County

In Texas, onsite wastewater systems (OSSF) are regulated at the state level (TCEQ) but implemented locally by the county health/environmental health office. In Walker County, you'll typically work with the Walker County Environmental Health Office for plan reviews, permits, and inspections, with state oversight from TCEQ. If you live inside a municipality, check whether the city issues its own septic permits in addition to county requirements.

Permits you may need

  • OSSF construction permit (state-level) administered through the local plan review process.
  • Local plan review and approval by Walker County Environmental Health Office before applying for the state permit.
  • Public or private water and wastewater requirements if your property is in a special hydraulic or flood zone.

Note: Always confirm exact permit steps with Walker County, as requirements can vary by property, lot size, and whether you're replacing, repairing, or enlarging an system.

Plan review, soil testing and design

A proper septic project starts with planned design and soil evaluation. Here's how to approach it:

  • Hire a licensed OSSF designer or engineer to prepare plans and a soil evaluation.
  • Conduct soil testing and site evaluations as required by state and local codes.
  • Prepare a detailed site plan, including proposed tank layout, drainage field, setback distances, and access for maintenance.
  • Submit plan documents to Walker County Environmental Health Office for local plan review.
  • After local approval, the plan moves to the state level for the construction permit (OSSF permit) through TCEQ, if required.

Inspections and maintenance

  • Construction inspections: A county inspector will typically verify that installation follows approved plans and setbacks before the system is buried.
  • Final certification: A final inspection and certification are usually required to close the permit.
  • Ongoing maintenance: Schedule regular pumping and inspection of the septic tank (commonly every 2–5 years depending on usage and tank size). Keep records of pumping, repairs, and inspections.
  • Repairs and upgrades: If you modify or repair the system, re-submit plans and obtain any necessary permits before work begins.

Getting started: a simple homeowner checklist

  1. Confirm whether Walker County requires a local plan review and permit for your project (and whether your municipality has its own requirements).
  2. Hire a licensed OSSF designer or installer to evaluate soil and prepare plans.
  3. Gather site information (lot size, setbacks, proximity to wells, streams, and structures).
  4. Submit plan documents to Walker County Environmental Health Office for review.
  5. Obtain the state OSSF construction permit (through TCEQ) if required.
  6. Schedule installation with a licensed contractor and arrange for inspections.
  7. After installation, obtain final approval and keep maintenance records.

Helpful resources

Cost Expectations for Septic Services in Walker County

Septic Tank Pumping

  • What it includes: Vacuum pumping of the tank to remove sludge and scum, verification of tank depth and baffles, and a basic system check for signs of distress. In Walker County, access to tanks can be affected by long driveways, rural gates, or uneven terrain, which may require more time or equipment.
  • Unique Walker County considerations: Clay soils and variable groundwater depths can influence pumping frequency and inspection findings. If the tank is buried under heavy brush or near outbuildings, access fees may apply.
  • Typical cost in Walker County: $275–$650 per pumping, with higher end for difficult access or oversized tanks.
  • Quick steps to prepare:
    1. Clear access to the tank lid.
    2. Notify occupants about the service date.
    3. Have records of previous pumpings available.
  • Official resource: https://www.tceq.texas.gov/permitting/ossf

Septic System Inspection (Non-Certified)

  • What it includes: Visual inspection of the components (tank lid, access risers, baffles, pump if present), check for Odors and surface indicators, basic flow testing, and notes on overall condition.
  • Unique Walker County considerations: Many homes are older with first-generation OSSFs; a non-certified inspection can help buyers or owners assess immediate needs before deeper work.
  • Typical cost in Walker County: $100–$250.
  • Quick steps to prepare:
    1. Gather any previous inspection reports.
    2. Identify any recurring issues (slow drains, gurgling, backups).
  • Official resource: https://www.tceq.texas.gov/permitting/ossf

OSSF Certification/Compliance Inspection

  • What it includes: Comprehensive site visit, tank and drain-field evaluation, measurement of system performance, notes on compliance with current rules, and documentation suitable for real estate transactions.
  • Unique Walker County considerations: Real estate transfers commonly trigger this inspection; some rural properties may require additional soil testing or mound-system considerations if soil percolation is marginal.
  • Typical cost in Walker County: $350–$700.
  • Quick steps to prepare:
    1. Schedule around closing timelines.
    2. Ensure access to the entire system (tank, drain field, and cleanout lids).
  • Official resource: https://www.tceq.texas.gov/permitting/ossf

Drain Field Repair or Replacement

  • What it includes: Diagnostic tests (percolation tests, soil evaluation), excavation, new drain lines or trenches, replacement or upgrading of the drain-field bed, and final system performance checks.
  • Unique Walker County considerations: Soil in parts of Walker County can be shallow or heavy clay, which may push projects toward mound systems or deeper excavations. Proximity to trees and root intrusion is a common factor.
  • Typical cost in Walker County: $8,000–$25,000 (larger or more complex installations can exceed this).
  • Quick steps to prepare:
    1. Obtain design options based on soil tests.
    2. Plan for any required permits and drainage considerations on-site.
  • Official resource: https://www.tceq.texas.gov/permitting/ossf

Drain Line Cleaning and Camera Inspection

  • What it includes: Video inspection of underground lines to locate blockages or breaks, hydro-jetting or mechanical cleaning of lines, and clearance testing.
  • Unique Walker County considerations: Tree roots and mineral buildup are common, especially on older lines; remote locations can add travel time and equipment fees.
  • Typical cost in Walker County: Camera inspection $150–$450; line cleaning $150–$500; combined often $300–$900.
  • Quick steps to prepare:
    1. Identify suspected problem areas (slow drains, backups).
    2. Keep access points clear for camera work.
  • Official resource: https://www.tceq.texas.gov/permitting/ossf

New System Installation

  • What it includes: Site evaluation, design plan, permitting, trenching or mound construction as required, tank installation, soil absorption system, and system start-up testing.
  • Unique Walker County considerations: Some parcels require mound systems or alternative designs due to soil depth or drainage; rural lots may demand longer trenches or more robust access paths for equipment.
  • Typical cost in Walker County: $10,000–$40,000 (often higher for complex soils or mound systems).
  • Quick steps to begin:
    1. Engage a licensed designer and installer familiar with Walker County soils.
    2. Obtain required permits and plan for seasonal weather impacts.
  • Official resource: https://www.tceq.texas.gov/permitting/ossf

Routine Maintenance Plans and Preventive Maintenance

  • What it includes: Scheduled pumpings, annual or semi-annual system checks, filter or pump inspections, record-keeping, and priority service alerts.
  • Unique Walker County considerations: Regular maintenance can extend system life on older OSSFs common in rural areas; keeping a maintenance calendar helps avoid costly surprises during busy seasons.
  • Typical cost in Walker County: $150–$500 per year, depending on service level and tank size.
  • Quick steps to establish a plan:
    1. Set a pumping interval based on household water use.
    2. Keep a service log with dates and findings.
  • Official resource: https://www.tceq.texas.gov/permitting/ossf

Emergency/Repair Services

  • What it includes: Rapid diagnostic, on-site repair or replacement of pumps, floats, valves, or liners; temporary containment if backups occur.
  • Unique Walker County considerations: Rural locations can mean longer travel times and higher after-hours fees; weather events can also impact access.
  • Typical cost in Walker County: Diagnostic call $100–$200; repairs $300–$2,500 for common fixes; major component replacements can exceed $5,000.
  • Quick steps to prepare:
    1. Have emergency contacts and access to utilities ready.
    2. Note any recent changes in drainage or backups.
  • Official resource: https://www.tceq.texas.gov/permitting/ossf

Tank Abandonment/Decommissioning

  • What it includes: Safe decommissioning of an unused tank, backfill, site restoration, and documentation for records.
  • Unique Walker County considerations: Decommissioning is common when selling vacant land or changing to non-OSSF disposal; adherence to state guidelines is important to avoid future issues.
  • Typical cost in Walker County: $1,000–$4,000.
  • Quick steps to prepare:
    1. Verify that the tank is indeed no longer in use.
    2. Obtain any needed permits or approvals.
  • Official resource: https://www.tceq.texas.gov/permitting/ossf

Cities & Communities in Walker County With Septic Systems

Huntsville

Huntsville includes areas served by the city sewer system and pockets where homes rely on septic systems. If you're unsure whether your property is connected, check with the City of Huntsville Public Works or the Walker County records.

  • Common septic system types you may encounter here
    • Conventional gravity septic
    • Aerobic treatment units (ATU)
    • Mound systems in soils with drainage or high water table
  • Quick maintenance checklist
    • Pump every 3–5 years (adjust for tank size and household size)
    • Conserve water to reduce waste in the system
    • Use septic-safe products; flush only toilet paper and human waste
    • Keep the drain field clear of vehicles, heavy equipment, and roots
  • If you notice a problem
    • Step 1: Limit water use to reduce load
    • Step 2: Visually inspect for soggy areas or odors and note changes
    • Step 3: Call a licensed septic contractor for inspection and pumping as needed
    • Step 4: For guidance or records, consult the Texas Commission on Environmental Quality's OSSF program
  • Official resources

New Waverly

Many homes in New Waverly rely on septic systems where sewer service isn't available. Confirm your status with local officials if you're unsure.

  • Likely system types
    • Conventional gravity septic
    • ATU systems
    • Mounds in challenging soils
  • Maintenance pointers
    • Regular pumping (3–5 years)
    • Water-saving fixtures and spacing laundry loads
    • Avoid flushing non-biodegradable items and fats/oils
  • If issues arise
    • 1) Limit wastewater until diagnosed
    • 2) Contact a licensed septic contractor for a pump/inspection
    • 3) Refer to TCEQ OSSF guidance if needed
  • Official resources

Riverside

Riverside includes rural areas where septic systems are common. Confirm whether your property uses sewer or septic through local records.

  • Typical systems you may see
    • Conventional septic
    • ATU
  • Care and maintenance
    • Pump on schedule, monitor for drain field signs, and manage water use
    • Protect drain field from heavy equipment and trees with deep roots nearby
  • What to do if you have problems
    • Step 1: Reduce water use
    • Step 2: Schedule inspection with a licensed pro
    • Step 3: If needed, contact TCEQ OSSF for guidance
  • Official resources

Point Blank

Point Blank and surrounding rural areas commonly use septic systems when sewer lines are not available.

  • System types you'll encounter
    • Conventional gravity
    • ATU
  • Maintenance basics
    • Regular pumping, water-use discipline, and drainage field protection
  • If you suspect a problem
    • 1) Pause heavy wastewater
    • 2) Call a licensed septic professional for evaluation
    • 3) Review OSSF guidance if you're seeking records or permits
  • Official resources

Unincorporated Areas (Walker County)

A large share of Walker County's septic users live in unincorporated areas where municipal sewer isn't available.

  • What to expect
    • Private septic systems are common
    • Records and status can be verified through county records and TCEQ OSSF
  • Steps to maintain health and reliability
    • 1) Locate your septic tank and drain field
    • 2) Schedule regular pumping and inspections
    • 3) Use water efficiently and avoid introducing harmful substances
  • Official resources

Septic vs Sewer Across Walker County

How Walker County sits between septic and sewer

Walker County blends rural parcels with growing towns. Many homes outside city limits rely on individual septic systems, while cities and larger developments are connected to municipal sewer. Your best option depends on where you live, access to utility lines, and long-term plans for the property.

Where sewer is available in Walker County

  • City utilities often serve the village centers and newer subdivisions.
  • If your property is inside a city or a recognized utility district, sewer connections are common and can be required for new builds.
  • Rural locations may not have a sewer main nearby, making septic the practical choice.

Pros and cons at a glance

  • Septic systems (on-site)
    • Pros: Lower monthly bills once installed; independence from public systems; suitable for rural lots without sewer access.
    • Cons: Regular pumping and maintenance; potential for failures if not properly cared for; local regulations can require upgrades if the system ages.
  • Public sewer
    • Pros: No septic tank maintenance; typically easier to manage long-term; system failures are handled by the utility.
    • Cons: Connection fees, impact fees, or taps; monthly sewer charges; possible repairs or rate changes by the utility.

Costs and maintenance to consider

  • Septic
    • Installation: varies with tank size, soil, and lot; typical residential tank projects in rural TX range broadly.
    • Ongoing: pumping every 3–5 years (more often with heavy use or failing soils); yearly inspections are helpful.
    • Repairs: soil tests or replacement leach fields can be expensive; regular pump-out helps prevent surprises.
  • Sewer
    • Connection costs: hookup fees, impact fees, and sometimes off-site work to bring the line to your property.
    • Ongoing: monthly service charges; fewer direct maintenance tasks for the homeowner, but you'll be billed for ongoing sewer usage.

Quick steps to decide and plan

  1. Check with the local utility or city at your address to see if sewer service is available or planned nearby.
  2. Verify property boundaries and zoning to determine eligibility for septic or sewer connections.
  3. If septic is your current option, have a licensed inspector assess tank size, condition, and leach field health.
  4. If sewer is available, obtain a cost estimate for connection and possible impact or tap fees.
  5. Plan for future: consider resale value, potential expansions, and replacement costs for either system.

Maintenance tips for septic systems in Walker County

  • Schedule regular pump-outs every 3–5 years (or per your installer's guidance).
  • Use water-efficient fixtures to reduce hydraulic load.
  • Avoid flushing non-biodegradables, fats, oils, and chemical cleaners.
  • Protect the leach field: discourage heavy machinery over the area; plant only shallow-rooted vegetation.
  • If you notice drainage backups, plumbing slowdowns, or odor, contact a licensed contractor promptly.

Helpful official resources

  • EPA Septic Systems overview:
  • Walker County official site (for local guidance and county-level regulations): https://www.co.walker.tx.us