What an AWTS costs — to buy, install and run
Written by Septic Help editors Prices checked against published installer pricing Last reviewed
An aerated wastewater treatment system (AWTS) — often called a home sewage treatment plant — treats wastewater to a standard you can irrigate the garden with. That capability costs money twice: once at install, and again every year you own it. Queensland installers publish $11,000–$16,000 for a new-build install; national guides put the range at $15,000–$25,000 once site works and approvals are counted. Replacing an existing septic tank with an AWTS is dearer again — typically $22,000–$30,000, because the old system has to be decommissioned and the site reworked.
Before comparing prices, make sure an AWTS is actually the right call for your block — the AWTS guide covers how they work and who they suit, and the brands guide covers the Taylex/Fuji Clean/Biocycle landscape.
| Item | Typical range | Notes |
|---|---|---|
| AWTS unit (supply only) | $8,000 – $15,000 | Brand, tank material (concrete vs poly) and capacity drive the spread |
| Site & soil assessment | $500 – $900 | Full LCA in VIC: $1,500–$3,000 |
| Council application fees | $400 – $1,200 | Permit to install; varies by LGA — see your state |
| Excavation & installation | $3,500 – $7,000 | Cranage for concrete tanks on tight sites adds more |
| Irrigation / land application area | $1,500 – $4,000 | Surface or subsurface drip lines; subsurface costs more |
| Electrical connection | $300 – $800 | AWTS needs permanent power and an alarm circuit |
Cost snapshot
A conventional septic system costs $8,000–$15,000 installed and next to nothing to run. If your soil passes the test for trenches, run both numbers over ten years before you sign — see the septic cost guide.
The running costs — what the brochure doesn't lead with
An AWTS is a small treatment plant with a blower, pumps and (usually) a chlorinator running around the clock. Every state requires it to be serviced by an accredited technician under an ongoing agreement — in NSW and QLD that generally means quarterly visits. These aren't optional extras; they're conditions of your council's approval to operate. The AWTS servicing requirements guide covers the rules; the numbers look like this:
| Cost | Typical range | Notes |
|---|---|---|
| Service contract (quarterly) | $700 – $1,600 /yr | $150–$400 per visit; chlorine tablets sometimes billed on top |
| Electricity | $200 – $500 /yr | Blower and pumps run continuously |
| Pump / aerator replacement | $500 – $1,500 | Each typically lasts around 5–10 years; budget ~$200/yr averaged |
| Desludge / pump-out | $600 – $900 | Every 5–10 years; dearer than a septic pump-out — more chambers |
| Council operating fee | $0 – $150 /yr | Some LGAs charge annual approval-to-operate or inspection fees |
What moves the price
- New build vs changeover. Swapping an old septic for an AWTS ($22,000–$30,000) costs far more than a new-build install, because of decommissioning and rework around existing services.
- Tank material. Concrete units cost more to buy and crane in, but sit better in high water tables; poly units are cheaper and lighter.
- Irrigation type. Subsurface drip costs more than surface sprays but is required by some councils and near boundaries.
- Access and distance. Cranage, long power runs and remote delivery all add real money.
- Council conditions. Sensitive catchments can require higher treatment standards or larger, dearer irrigation fields.
Check your council
Councils approve the install and set the servicing conditions you'll live with — NSW councils such as Hornsby publish quarterly-servicing requirements for every AWTS. Find your state's approval process before you buy a brand your local technicians don't service.
AWTS cost questions
Why is an AWTS so much dearer than a septic tank?
You're buying a powered treatment plant, not a passive tank — blower, pumps, chlorinator, alarm and controls — plus an irrigation field. Then quarterly servicing and power add $1,000–$2,000 every year for the life of the system.
Is the service contract really mandatory?
Yes. Ongoing servicing by an accredited technician is a condition of your council approval in every state, and most councils require reports after each visit. Skipping it risks compliance action and voids most warranties. See what a contract covers.
What does an AWTS cost over 10 years?
Roughly $12,000–$25,000 to install plus $10,000–$20,000 in servicing, power, parts and desludging — call it $25,000–$45,000 all-in. A conventional septic over the same decade typically costs under $17,000 including install.
Can I reduce running costs by servicing it myself?
No — the servicing must be done by an accredited service agent under your approval conditions. You can cut costs at the margins by keeping the irrigation area healthy and not overloading the system, which reduces callouts and early pump failures.
Does an AWTS still need pumping out?
Yes. Sludge still accumulates and needs removing roughly every 5–10 years, at around $600–$900. Your service technician monitors sludge levels and tells you when it's due.