New Construction Septic System in Texas (2026 Guide)
New construction septic systems in Texas cost $8,000-$12,000 for conventional or $12,000-$25,000 for aerobic. Permits take 4-10 weeks from application to final inspection.
How Much Does a New Construction Septic System Cost in Texas?
New construction septic systems in Texas cost $8,000-$12,000 for conventional or $12,000-$25,000 for aerobic. Permits take 4-10 weeks from application to final inspection.
Building a new home on land without city sewer means you need a septic system, and Texas has specific rules about how that process works. TCEQ (Texas Commission on Environmental Quality) requires a permit before any septic work begins, and your county handles the actual approval.
This guide walks you through every step, from soil testing to final inspection.
As Nathan Glavy, Extension Program Specialist at Texas A&M's Texas Water Resources Institute, advises in the OSSF education program, getting your site evaluation done early is the single most important step in new construction, because it determines your system type, cost, and even where you can place the house on the lot.
What Is the Texas Septic Permit Process?
Every new septic system in Texas requires a permit from your county's TCEQ-authorized agent before construction can begin. There's no shortcut around this.
Here's the full process:
- Hire a licensed site evaluator. They'll test your soil and assess your property. This is the first step before anything else happens.
- Complete the site evaluation. The evaluator performs a perc test and soil analysis to determine what type of system your property can support.
- System design. Based on the site evaluation, a licensed designer or installer creates plans showing tank location, drain field layout, and all required setbacks.
- Submit permit application. Your installer or designer submits the application to your county with the site evaluation report, system design plans, and application fee.
- County review. The county reviews your application. This takes 2 to 4 weeks depending on the county's workload and whether your application is complete.
- Authorization to Construct. Once approved, you receive written permission to begin installation.
- Installation. Your licensed installer builds the system, with county inspections at key stages.
- Final inspection. The county inspects the completed system before it's covered with soil.
- Operating permit issued. After passing final inspection, you receive your operating permit.
Common delays:
- Incomplete applications (missing soil reports, incorrect setback measurements) can add 1 to 2 weeks
- Aerobic systems require a signed two-year maintenance contract before the permit is issued
- Some counties have longer review periods during busy building seasons
System Sizing: How Big Does Your Septic Need to Be?
Septic system size in Texas is based on the number of bedrooms in your home and your property's soil conditions, not the number of people living there.
TCEQ uses bedrooms as a proxy for maximum potential occupancy. Here's how sizing typically works:
| Number of Bedrooms | Minimum Tank Size | Estimated Daily Flow |
|---|---|---|
| 1-2 bedrooms | 750 gallons | 300 gallons/day |
| 3 bedrooms | 1,000 gallons | 450 gallons/day |
| 4 bedrooms | 1,250 gallons | 600 gallons/day |
| 5 bedrooms | 1,500 gallons | 750 gallons/day |
| 6+ bedrooms | Custom sizing required | 150 gallons/bedroom/day |
The drain field size depends on your soil's drainage rate from the perc test. Slower-draining soil needs a larger drain field to handle the same volume of wastewater. Your site evaluator and system designer calculate this based on your specific soil data.
Things that affect sizing beyond bedrooms:
- Garbage disposals increase the load on your system (some evaluators add 50% to tank size)
- Hot tubs or high-flow fixtures can require upsizing
- Home offices that generate additional wastewater (like photography studios with darkrooms)
- Guest houses or accessory dwelling units on the property
How Much Does a New Construction Septic Cost?
Plan to spend $8,000 to $12,000 for a conventional system or $12,000 to $25,000 for an aerobic system, plus $500 to $1,500 in permit and evaluation fees.
| Cost Category | Conventional System | Aerobic System |
|---|---|---|
| Site evaluation and perc test | $250 - $600 | $250 - $600 |
| Permit fees | $300 - $800 | $400 - $1,000 |
| Septic tank | $800 - $2,000 | $1,500 - $3,000 |
| Drain field / spray heads | $3,000 - $6,000 | $4,000 - $8,000 |
| Pump and electrical | $0 - $500 | $1,500 - $3,500 |
| Treatment unit | N/A | $3,000 - $6,000 |
| Labor and installation | $2,500 - $4,000 | $3,000 - $5,000 |
| Total | $8,000 - $12,000 | $12,000 - $25,000 |
What drives costs higher:
- Rocky soil or difficult digging conditions
- Long distance from house to suitable drain field location
- Steep slopes requiring special engineering
- Alternative systems (mound, drip irrigation) for challenging sites can push costs to $30,000+
- Remote properties with higher delivery and equipment costs
What's not included: These estimates cover the septic system itself. You'll also need plumbing from the house to the tank, which your general contractor or plumber typically handles as part of the home's plumbing.
How Long Does the Process Take?
Expect 4 to 10 weeks from your first call to a completed, inspected septic system. Weather, county processing times, and system complexity all affect the schedule.
| Phase | Timeframe |
|---|---|
| Site evaluation and perc test | 3 - 7 days |
| System design | 3 - 7 days |
| Permit application and county review | 2 - 4 weeks |
| Installation (conventional) | 1 - 3 days |
| Installation (aerobic) | 3 - 5 days |
| Final inspection | 1 - 3 days after installation |
Tips to keep your timeline on track:
- Start the site evaluation as early as possible. It should be one of the first things you do after buying land.
- Submit a complete permit application the first time. Missing documents are the most common cause of delays.
- Schedule your installer early. Good septic companies in growing areas like the Hill Country and DFW suburbs book out weeks in advance.
- Coordinate with your builder so septic installation fits into the overall construction schedule (typically after foundation but before landscaping).
Should You Choose Conventional or Aerobic?
Your soil conditions largely dictate this choice. Conventional systems work for well-draining soil, while aerobic systems are required for poor soil, small lots, or properties near sensitive water sources.
| Factor | Conventional | Aerobic |
|---|---|---|
| Upfront cost | $8,000 - $12,000 | $12,000 - $25,000 |
| Annual maintenance cost | $300 - $500 (pumping every 3-5 years) | $600 - $1,200 (required inspections + pumping) |
| Requires electricity | No | Yes |
| Maintenance contract required | No | Yes (TCEQ mandate) |
| Minimum lot size | Larger (need room for drain field) | Can work on smaller lots |
| Soil requirements | Good drainage (5-60 MPI) | Works with poor drainage |
| Moving parts | None | Pumps, aerator, control panel |
| Noise | Silent | Aerator makes a low hum |
When Texas requires aerobic:
- Soil fails a perc test for conventional
- Lot is too small for an adequate drain field
- Property is in the Edwards Aquifer recharge zone or other environmentally sensitive area
- High water table prevents standard drain field operation
When you can choose conventional:
- Soil drainage is good (5 to 60 MPI on the perc test)
- Lot has enough space for the drain field (typically 2,000 to 5,000+ square feet depending on soil)
- No environmental restrictions require advanced treatment
- You want lower ongoing maintenance costs and complexity
If your soil supports conventional, most installers recommend going that route for new construction. Fewer moving parts means fewer things that can break.
Who Is Responsible: Builder or Homeowner?
The builder typically coordinates the septic installation for new construction, but the homeowner is ultimately responsible for the permit and system maintenance.
| Responsibility | Builder | Homeowner |
|---|---|---|
| Scheduling site evaluation | Usually | Sometimes |
| Paying for site evaluation | Split varies | Split varies |
| Submitting permit application | Often handles | Signs as owner |
| Choosing septic installer | Recommends | Approves |
| Paying for installation | Included in build contract, or separate | Depends on contract |
| Signing maintenance contract (aerobic) | No | Yes, required |
| Post-construction maintenance | No | Yes |
| Warranty claims | May coordinate in year 1 | Ongoing |
Important notes for homeowners building custom homes:
- Get the septic system as a separate line item in your construction contract so you can see what you're paying
- Ask your builder which septic company they use and check that company's license with TCEQ
- If you're acting as your own general contractor, you're responsible for coordinating the entire process
- The operating permit is issued in the homeowner's name, and you're responsible for all future maintenance
- For aerobic systems, the two-year maintenance contract starts when the system is activated, not when the house is finished
What Are the Perc Test Requirements for New Builds?
A perc test is required for virtually all new construction septic systems in Texas, and it must be performed by a TCEQ-licensed site evaluator.
The perc test is your first step because everything else depends on the results. Your system type, size, drain field location, and cost all flow from what the soil evaluation reveals.
Get your perc test done before you finalize your home's floor plan if possible. In some cases, the septic system location affects where you can place the house on the lot due to setback requirements (minimum distances from the tank and drain field to the house, wells, property lines, and water bodies).
For a detailed breakdown of the perc test process, costs, and what happens if your test fails, see our complete perc test guide.
What Should You Do Next?
If you're planning new construction on land without sewer service:
- Contact your county's permitting office to understand local requirements and fees
- Hire a licensed site evaluator to perform a soil evaluation and perc test
- Get the perc test done early so results can inform your home design and budget
- Get quotes from 2-3 licensed septic installers once you have your site evaluation results
- Coordinate with your builder on timeline and responsibilities
Ready to get started? Find licensed septic installers in your area
Frequently Asked Questions
Can I install a septic system myself for new construction in Texas?
No. Texas law requires a licensed installer to construct septic systems. The installer must hold a valid TCEQ license, and the county inspects the work at multiple stages. Even if you're handy with excavation equipment, DIY installation won't pass inspection and can result in fines. The only exception is very basic maintenance like pumping, which doesn't require a license.
How far does a septic system need to be from a well in Texas?
TCEQ requires a minimum of 50 feet between a septic tank and a private water well, and 100 feet from the drain field to the well. Some counties have stricter requirements, especially in areas with vulnerable aquifers like the Edwards Aquifer region. If you have a tight lot, these setbacks can significantly affect where both the well and septic system can go. Work with your site evaluator early to map out these constraints.
Do I need a septic system if my property is 10 acres or more?
You still need a septic system, but you may be exempt from the permit requirement under Texas's 10-acre exemption. The exemption applies only to single-family homes on 10+ acres where the system is at least 100 feet from all property lines. Even if you qualify, getting a proper site evaluation and professional installation is strongly recommended. A failed unpermitted system can cost far more to fix than doing it right the first time.
How long does a new septic system last in Texas?
A well-installed conventional septic system in Texas lasts 25 to 40 years or more with proper maintenance. Aerobic systems have a similar lifespan for tanks, but mechanical components (pumps, aerators) typically need replacement every 10 to 15 years. Regular pumping, proper use, and keeping heavy vehicles off the drain field are the biggest factors in longevity. See our guide to septic system lifespan for more details.
What if my builder wants to use a different septic company than I prefer?
You have the right to choose your own septic installer, but check your construction contract first. Some builder contracts specify that the builder selects all subcontractors. If you have a preferred septic company, negotiate this before signing the build contract. The key qualifications to look for are a valid TCEQ installer license, experience with your specific system type, and good references from recent Texas installations.
Last updated: February 2026 Reviewed by: Texas Septic Guide Editorial Team, TCEQ regulatory research
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