Texas Septic Help

Aerobic vs conventional septic systems in Texas

A conventional system settles solids in a tank and lets the soil finish treating the liquid; an aerobic unit pumps air into the wastewater, treats it further and usually sprays it on the yard after disinfection. In Texas the site evaluation usually decides which one a lot can use. [1] [2] [3]

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Cost figures are estimates published by commercial cost guides, not quotes. Get written, itemized bids for the same approved design.

How the two types differ

Conventional septic system and aerobic treatment unit compared
Conventional (septic tank and drain field)Aerobic treatment unitSource
How it treatsThe tank settles solids; the liquid flows to a drain field where the soil finishes treatment.A pretreatment (trash) tank, then an aeration chamber where an air pump feeds oxygen-using bacteria, then a settling chamber, disinfection and usually a spray field.[1], [2]
Treatment levelAgriLife says the tank lowers biochemical oxygen demand by more than 65 percent and suspended solids by more than 70 percent before the soil does the rest.AgriLife says aerobic units remove 85 to 98 percent of organic matter and solids.[1], [2]
PowerA gravity system keeps working in a power outage.Needs continuous power for the air pump; pumps and alarms also run on power.[4], [2]
SoilAgriLife says a standard drain field cannot be used in clay soil.Often used where the soil or site rules out a standard drain field.[1], [3]
PumpingTCEQ recommends every three to five years.TCEQ says it depends on sludge depth and the manufacturer's recommendations; AgriLife suggests a schedule similar to a septic tank, every 2 to 3 years.[5], [2]

Which one you get

The site usually decides

Before a permit is issued, a licensed Site Evaluator or professional engineer surveys the lot and analyzes the soil where the disposal area will go to decide which systems suit it. Texas rules group soils into types I to IV; clay is type IV, and AgriLife says a standard drain field cannot be used in clay. [3] [6] [1]

How common spray systems are

In 2025, 24,392 of the 41,990 septic permits (authorizations to construct) issued by Texas authorized agents were for surface (spray) irrigation, a little under three in five. In Montgomery County it was 1,469 of 1,821, and in Rockwall County 47 of 51. [7]

See also: Septic system permits issued (authorizations to construct) in 2025 by each county as TCEQ's authorized agent

Clay around Dallas, Austin and San Antonio

Texas Septic Guide, a commercial cost guide, says the Blackland Prairie clay from Dallas through Austin to San Antonio drains too slowly for conventional drain fields, so most installations there need aerobic treatment. [8]

What a spray system is

A surface application system sprays treated effluent onto the ground. Texas rules require it to be disinfected first, and AgriLife notes the rules prohibit applying effluent to vegetable gardens because some pathogens resist disinfection. [9] [10]

Upkeep each type needs

Conventional system

TCEQ recommends pumping every three to five years and says not to drive or park over any part of the system or build over it. [5] [11]

See also: TCEQ's pumping table

Aerobic system: the state rule

A system starts with a two-year service policy. After that, the owner of a single-family home must either sign a new contract with a licensed Maintenance Provider or maintain the system personally. A provider under contract tests and reports at least every four months. Owners who maintain their own system are exempt from the state testing and reporting rule, but some local authorities require training or ban homeowner maintenance. [12] [5]

See also: What state rules require

Chlorine

Where chlorine tablets are used, TCEQ says to use calcium hypochlorite tablets certified for wastewater disinfection, never swimming pool tablets, which dissolve too slowly to disinfect and can release an explosive gas. [5]

Keep the power on

AgriLife says not to turn off power to a system with mechanical parts, even when you're away: sewage that collects while the power is off is untreated and may be sprayed when power comes back. [13]

How to tell which one you have

Check the permit file

The permit and plans on file with your permitting authority show the system type. TCEQ's OARS lookup lists the authority for your county. [14] [15]

Signs of an aerobic system

A maintenance tag on the motor cover, control panel or breaker box, which state rules require on aerobic systems under contract; a chlorinator or other disinfection unit; and spray heads in the yard. [12] [9]

Published installation costs

Where the numbers come from

Both figures below come from commercial cost guides that also offer to put readers in touch with contractors. No independent survey of Texas installation prices turned up, so the ranges sit side by side instead of being averaged. Both pages were read on Oct 7, 2026. [8] [16]

Published installation estimates for Texas
PublisherConventionalAerobicWhat the publisher says the figure is based onSource
Texas Septic Guide$6,300 to $10,000$10,000 to $20,000HomeAdvisor and Angi national data, its own 2025-2026 provider surveys, TCEQ permit fee schedules and county records. Site evaluation, permits and engineering add $1,500 to $5,000.[8]
Nearby Septic, citing Dillon Septic and Angi$7,000 to $12,000 (one Hill Country installer's pages)$10,000 to $20,000; complex projects $26,000 or moreOne Hill Country installer's published ranges (Dillon Septic) and Angi's national guide.[16]
Running costs for an aerobic system

One cost guide, Texas Septic Guide, estimates $100 to $300 a year for electricity and $300 to $500 a year for a maintenance contract. Another, Nearby Septic, says it found no current published Texas contract price. [17] [18]

See also: What contracts cost

Comparing bids

TCEQ suggests getting at least three estimates and asking any installer whose price is far from the others what it added or left out. It also suggests asking what a required maintenance contract will cost after the first two years. [11]

Power outages

Why water use matters

A powered system only holds a small reserve. AgriLife explains that state rules require reserve capacity of one-third of a day's design flow, which is 80 gallons for a three-bedroom home; one 10-minute shower uses about 25 gallons. [4]

  1. During the outage, limit water to essentials such as flushing and hand washing, and stop all use if the outage is long or drains slow down.
  2. After power returns, hold off on laundry and dishwashing for a day if the outage lasted more than a day.
  3. For a spray system after a long outage, make sure disinfection is working and stay off the spray area while it's wet.
  4. Call your service provider if the high-water alarm stays on for more than 24 hours.

Source: [4] Texas A&M AgriLife Extension

About this page

How a conventional septic system and an aerobic treatment unit differ in Texas: how each treats wastewater, what the site has to do with the choice, the upkeep each needs, published install costs, and what to do in a power outage.

Key facts
Covers
  • How conventional and aerobic systems treat wastewater
  • Why the site evaluation, not the owner, usually decides the type
  • How common spray (surface irrigation) systems are in Texas permits
  • Upkeep rules for each type
  • Published installation cost estimates
  • How to tell which type you have
  • Power outages with a powered system
Not covered
  • Maintenance contract details (see the aerobic contract page)
  • Prices from any specific company, or a quote
Jurisdiction
Texas, United States (statewide). Includes 2025 permit counts for Houston-area and Dallas-Fort Worth counties.
Audience
Texas homeowners, buyers and landowners who have, or are being told they need, a conventional or aerobic septic system (on-site sewage facility, OSSF).
Provides
  • A side-by-side comparison table
  • A table of published installation estimates, each linked to its source
  • Steps for a power outage
Content last changed
Last verified
Primary sources

Price estimates come from commercial cost guides, listed in Sources.

Other formats
Markdown version

Contacts

Sources

Each fact above cites one or more of these by number. Accessed is the date the source was last re-read.

  1. [1] Onsite wastewater treatment systems: Septic tank/soil absorption field (L-5227). Texas A&M AgriLife Extension. Primary source.
    Supports: How a conventional system treats; treatment percentages; soil types; no standard drain field in clay (2008).
    Publisher's date: Fact sheet dated September 2008.
    Accessed: .
  2. [2] Onsite wastewater treatment systems: Aerobic treatment unit (L-5302). Texas A&M AgriLife Extension. Primary source.
    Supports: How an aerobic unit works; 85 to 98 percent removal; continuous power; pumping every 2 to 3 years (2008).
    Publisher's date: Fact sheet dated September 2008.
    Accessed: .
  3. [3] Getting a Permit for an OSSF - Such as a Septic System. Texas Commission on Environmental Quality (TCEQ). Primary source.
    Supports: Site evaluation by a licensed Site Evaluator or engineer decides suitability.
    Publisher's date: Page last modified 2026-08-10.
    Accessed: .
  4. [4] Onsite wastewater treatment systems: Responding to power outages and floods (L-5475). Texas A&M AgriLife Extension. Primary source.
    Supports: Gravity systems keep working in an outage; reserve capacity; outage steps (2008).
    Publisher's date: Fact sheet dated September 2008.
    Accessed: .
  5. [5] Maintenance of On-Site Sewage Facilities (Septic Systems). Texas Commission on Environmental Quality (TCEQ). Primary source.
    Supports: Pumping intervals; maintenance provider testing and reporting; local rules; chlorine type.
    Publisher's date: Page last modified 2026-03-03.
    Accessed: .
  6. [6] Occupational Licenses: On-Site Sewage Facilities (Septic Systems). Texas Commission on Environmental Quality (TCEQ). Primary source.
    Supports: Site Evaluators perform pre-construction site evaluations.
    Publisher's date: Page last modified 2026-03-24.
    Accessed: .
  7. [7] Types of Systems Installed by Time Period, 1/1/2025 to 12/31/2025. Texas Commission on Environmental Quality (TCEQ). Primary source.
    Supports: 2025 statewide, Montgomery and Rockwall permit and surface irrigation counts.
    Publisher's date: Report dated 2026-04-27.
    Accessed: .
  8. [8] How Much Does a Septic System Cost in Texas? [2026 Data]. Texas Septic Guide. Commercial cost guide.
    Supports: Blackland Prairie clay statement; Texas installation ranges; added site evaluation, permit and engineering cost; its stated survey method.
    Publisher's date: Page says last verified 2026-03-09.
    Accessed: .
  9. [9] 30 Tex. Admin. Code § 285.33, Criteria for Effluent Disposal Systems. Texas Administrative Code, via Cornell Legal Information Institute. Primary source.
    Supports: Surface application systems spray treated effluent, which must be disinfected first.
    Accessed: .
  10. [10] Living with an aerobic treatment unit and spray field (B-6234). Texas A&M AgriLife Extension. Primary source.
    Supports: Rules prohibit effluent on vegetable gardens (2010).
    Publisher's date: Bulletin dated January 2010.
    Accessed: .
  11. [11] Advice for an Owner of an On-Site Sewage Facility (Septic System). Texas Commission on Environmental Quality (TCEQ). Primary source.
    Supports: Don't build, drive or park over the system; three estimates; ask about contract cost after two years.
    Publisher's date: Page last modified 2026-03-03.
    Accessed: .
  12. [12] 30 Tex. Admin. Code § 285.7, Maintenance Requirements. Texas Administrative Code, via Cornell Legal Information Institute. Primary source.
    Supports: Two-year service policy; contract or self-maintenance; self-maintainers exempt from testing; maintenance tag location.
    Accessed: .
  13. [13] Onsite wastewater treatment systems: Understanding and maintaining your septic system (L-5491). Texas A&M AgriLife Extension. Primary source.
    Supports: Don't turn off power to a system with mechanical parts (2008).
    Publisher's date: Fact sheet dated September 2008.
    Accessed: .
  14. [14] 30 Tex. Admin. Code § 285.3, General Requirements. Texas Administrative Code, via Cornell Legal Information Institute. Primary source.
    Supports: Permit and approved plans on file.
    Accessed: .
  15. [15] OARS: Find a Local Contact (septic permitting authority by county). Texas Commission on Environmental Quality (TCEQ). Primary source.
    Supports: Finding the local permitting authority.
    Accessed: .
  16. [16] Aerobic Septic System Cost in Texas (2026). Nearby Septic. Commercial cost guide.
    Supports: Texas aerobic and conventional installation ranges from one installer's pages and Angi.
    Accessed: .
  17. [17] Septic System Maintenance Cost in Texas [2026 Data]. Texas Septic Guide. Commercial cost guide.
    Supports: Aerobic electricity and contract cost estimates.
    Publisher's date: Page says last verified 2026-03-09.
    Accessed: .
  18. [18] Aerobic Maintenance Contracts in Texas (2026). Nearby Septic. Commercial cost guide.
    Supports: No current published Texas contract price.
    Accessed: .

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