Updated September 16, 2026
Short answer
A new residential septic system from Quick Flow Septic runs $9,000–$15,500 installed in the Houston region: about $9,000 for a conventional gravity system where the soil allows one, $13,500 for an aerobic (ATU) system with spray dispersal, and $15,500 for an aerobic system with drip dispersal — plus the county permit fee ($575 in Fort Bend County, $275 in Liberty County, and $210–$420 in most other area counties). Most lots here grade out clay-heavy under TCEQ rules (30 TAC Chapter 285) and need an aerobic system, while a conventional system sits at the low end where the soil drains well. The system type your soil calls for is the biggest cost driver — so the only way to a firm number is a free on-site soil evaluation.
What drives the price
The single biggest factor is the system type your soil and perc results call for. A conventional gravity system is the most affordable; an aerobic treatment unit with spray dispersal costs more; and an aerobic unit with drip dispersal sits at the top. Better-draining soil can qualify for the conventional field, while the tight clay common around Houston pushes the design into aerobic. The county permit fee and unusually difficult site access add to it.
Flat pricing by system type
Our installed pricing is flat by system type — $9,000 conventional, $13,500 aerobic with spray, $15,500 aerobic with drip — so a bigger house doesn't automatically mean a bigger bill. Home size still matters to the design: bedroom count and square footage set your TCEQ design flow, which sizes the tank and the dispersal field. The tables below show the installed price by system type, and how TCEQ 30 TAC Ch. 285 design flow scales with home size — the same sizing our instant estimator runs.
Conventional vs. aerobic cost
A conventional gravity system ($9,000 installed) is the most affordable option where soil percolates well and there's room for a standard field. An aerobic treatment unit costs more — $13,500 with spray dispersal or $15,500 with drip — but it's required on the tighter, clay-heavy soils common across the Houston metro, or on smaller lots where a conventional field won't pass.
Aerobic septic system cost in Texas
An aerobic septic system costs $13,500 installed with spray dispersal or $15,500 with drip dispersal from Quick Flow Septic — flat. That price covers the aerobic treatment unit (ATU) and its tanks, the control panel and alarm, the spray heads or the drip field, the site evaluation, the TCEQ-compliant design, the county permit filing, and installation. Aerobic units also carry an ongoing cost that conventional systems don't: TCEQ requires a maintenance contract with a licensed provider (the initial contract runs two years), so budget for that service on top of the install. Our aerobic maintenance guide covers what the visits involve.
Cost by county: the permit fee is the only local variable
Because the installed price is flat, the only number that changes from one county to the next is the fee the county's OSSF permitting authority charges. Where a county publishes its single-family fee we print it; where it doesn't (Harris, Montgomery, Waller, and Wharton) we confirm the current amount during permitting and pass it through at cost. The county table further down adds each published fee to the three installed prices, so you can see the full installed cost for your county.
What's included — and what isn't
Included in the flat price: the on-site soil evaluation and borings TCEQ requires, the system design, the county permit filing and final inspection, the tank(s), the treatment unit on aerobic systems, the drainfield, spray, or drip dispersal system, and the installation itself. Not included: the county permit fee (passed through at cost) and unusually difficult site access (heavy clearing or rock, for example), which we price and explain before any work starts.
How to get your exact price
Use our instant estimator for a ballpark in under a minute. The exact price comes after a free on-site soil evaluation, since your soil class decides the system type — and the system type is the price.
Free tool
Will your lot need an aerobic system? Check the address.
USDA soil rating, FEMA flood zone, and mapped wetlands for any Texas address — plus the system type and flat price you're likely looking at. About ten seconds, no account.
Installed price by system type
| System type | Installed price | Best for |
|---|---|---|
| Conventional gravity | $9,000 | Well-draining soil with room for a standard drainfield |
| Aerobic (ATU) + spray | $13,500 | Clay-heavy lots — the most common install in this area |
| Aerobic (ATU) + drip | $15,500 | Tight clay, smaller lots, or irregular sites |
TCEQ design flow by home size (sizes the tank & field)
| Home size | TCEQ design flow |
|---|---|
| 2-bedroom | 180 GPD |
| 3-bedroom | 240 GPD |
| 4-bedroom | 300 GPD |
| 5-bedroom | 360 GPD |
Installed cost by county (flat price + published county permit fee)
| County | Permit fee | Conventional | Aerobic + spray | Aerobic + drip |
|---|---|---|---|---|
| Harris | Set at application | $9,000 + county fee | $13,500 + county fee | $15,500 + county fee |
| Montgomery | Set at application | $9,000 + county fee | $13,500 + county fee | $15,500 + county fee |
| Fort Bend | $575 | $9,575 | $14,075 | $16,075 |
| Waller | Set at application | $9,000 + county fee | $13,500 + county fee | $15,500 + county fee |
| Liberty | $275 | $9,275 | $13,775 | $15,775 |
| Washington | $325 | $9,325 | $13,825 | $15,825 |
| Grimes | $420 | $9,420 | $13,920 | $15,920 |
| San Jacinto | $310 | $9,310 | $13,810 | $15,810 |
| Walker | $210 | $9,210 | $13,710 | $15,710 |
| Colorado | $250 | $9,250 | $13,750 | $15,750 |
| Austin | $275–$375 | $9,275–$9,375 | $13,775–$13,875 | $15,775–$15,875 |
| Wharton | Set at application | $9,000 + county fee | $13,500 + county fee | $15,500 + county fee |
Frequently asked questions
How much does a new septic system cost in Texas?
From Quick Flow Septic, $9,000–$15,500 installed in the Houston region: about $9,000 for a conventional gravity system where the soil allows one, $13,500 for an aerobic (ATU) system with spray dispersal, and $15,500 for an aerobic system with drip. Most lots in this area grade out clay-heavy and need an aerobic system; the county permit fee is on top.
Why does an aerobic system cost more than a conventional one?
An aerobic treatment unit (ATU) adds a powered treatment tank and a spray or drip dispersal system — more equipment and labor than a conventional gravity field. That's why it runs $13,500 (spray) or $15,500 (drip) versus about $9,000 for a conventional system. It's required where the soil is too tight or the lot too small for a conventional field to pass.
Does soil type really change the price?
Yes — because it decides the system type, and the system type sets the price. Well-draining soil can qualify for a $9,000 conventional field, while tight, clay-heavy soil (TCEQ Class IV) usually forces an aerobic system at $13,500 with spray or $15,500 with drip. That's why an on-site soil/perc evaluation sets the final price.
What's included in the installed price?
The installed price covers the tank, the treatment unit on aerobic systems, the dispersal system (drainfield, spray, or drip), and the installation itself. County permit fees and unusually difficult site access can add to it — we spell out exactly what's included before any work begins.
Is the online estimate a firm quote?
No. The instant estimate gives an honest range based on TCEQ 30 TAC Ch. 285 sizing. The exact price is set after a free on-site soil evaluation, since your soil class decides which system your lot needs.
Do you charge for an estimate?
No — estimates are free. We evaluate your site before providing a firm price.
Which areas do you serve?
We install new septic systems across 12 Texas counties in the greater Houston region: Harris, Montgomery, Fort Bend, Waller, Liberty, Washington, Grimes, San Jacinto, Walker, Colorado, Austin, and Wharton.
How much does an aerobic septic system cost in Texas?
From Quick Flow Septic, $13,500 installed with spray dispersal or $15,500 with drip dispersal, flat — plus the county permit fee. Aerobic systems are what most clay-heavy lots in the Houston region end up with, because TCEQ does not allow a conventional drainfield in Class IV clay.
How much is the septic permit fee in my county?
Published single-family OSSF fees in the counties we serve: Fort Bend $575, Grimes $420, Washington $325, San Jacinto $310, Liberty $275, Austin $275–$375, Colorado $250, and Walker $210. Harris, Montgomery, Waller, and Wharton set the fee at application — we confirm it and pass it through at cost.
Does a bigger house cost more?
Not automatically. The installed price is flat per system type. A bigger house raises the TCEQ design flow, which sizes the tank and the dispersal field, but the price you pay is still the flat price for the system type your soil calls for.
Quick Flow Septic installs new septic systems across Harris County · Montgomery County · Fort Bend County · Waller County · Liberty County · Washington County · Grimes County · San Jacinto County · Walker County · Colorado County · Austin County · Wharton County.
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