Updated June 15, 2026
Short answer
A new residential septic system in the Houston area typically runs from about $12,000 for a smaller system to $20,000+ for a larger one. Most lots here need an aerobic (ATU) drip system, while a conventional gravity system sits at the lower end where the soil allows. Your soil class, system size, and the drainfield size are the biggest cost drivers — so the only way to a firm number is a free on-site soil evaluation.
What drives the price
The biggest factors are your soil and perc results (better-draining soil needs a smaller, cheaper drainfield), the system type your soil allows, your tank size (set by bedroom count), and the drainfield's linear footage. Site access and county permitting add to it.
Cost by home size
Larger homes need more wastewater capacity (a higher TCEQ design flow), which means a bigger tank and a longer drainfield — and a higher price. The table below shows typical installed ranges by bedroom count, using the same TCEQ 30 TAC Ch. 285 sizing as our instant estimator.
Conventional vs. aerobic cost
A conventional gravity system is the most affordable option where soil percolates well and there's room for a standard field. An aerobic treatment unit (ATU) with drip dispersal costs more, 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.
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 is the single biggest cost driver.
Typical cost by home size
| Home size | TCEQ design flow | Typical installed cost |
|---|---|---|
| 2-bedroom | 180 GPD | $12,000–$14,000 |
| 3-bedroom | 240 GPD | $12,000–$14,000 |
| 4-bedroom | 300 GPD | $14,000–$18,000 |
| 5-bedroom | 360 GPD | $14,000–$20,000 |
Conventional vs. aerobic
| System type | Typical installed cost | Best for |
|---|---|---|
| Conventional gravity | From ~$12,000 | Good-draining soil with room for a standard drainfield |
| Aerobic (ATU) + drip | ~$12,000–$20,000+ | Tight/clay soils — most lots in this area |
Frequently asked questions
How much does a new septic system cost in Texas?
A new residential system in the Houston area typically runs from about $12,000 for a smaller system to $20,000+ for a larger one. Most lots in this area need an aerobic (ATU) drip system; a conventional gravity system sits at the lower end where the soil allows. Soil class, system size, and drainfield size are the biggest drivers.
Why does an aerobic system cost more than a conventional one?
An aerobic treatment unit (ATU) adds a powered treatment tank and a drip dispersal field — more equipment and labor than a conventional gravity field. 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 — it's the single biggest factor. Tighter, clay-heavy soil (TCEQ Class IV) needs a larger drip field than well-draining soil (Class III), and a bigger field costs more. That's why an on-site soil/perc evaluation sets the final price.
What's included in the installed price?
A typical installed price covers the septic or aerobic treatment tank, the dispersal system (drainfield or drip), and installation. County permit fees and 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 drives the cost.
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 Harris, Montgomery, Fort Bend, Waller, and Liberty counties in the greater Houston area.
Quick Flow Septic installs new septic systems across Harris County · Montgomery County · Fort Bend County · Waller County · Liberty County.
Ready for a real number?
Get your instant estimate, or call and we'll schedule a free on-site evaluation.