AWTS stands for Aerated Wastewater Treatment System, an on-site sewage treatment system that actively treats household wastewater using air, bacteria, and (usually) disinfection, rather than relying almost entirely on the soil to finish the job the way a standard septic tank does. If you’ve had a quote mention “AWTS” alongside a bigger number than expected, this is exactly what you’re paying for, and why it’s often the only option approved on smaller or trickier blocks.
Here’s what an AWTS actually is, how it compares to a standard septic tank and an ATU, what it costs in Australia in 2026, and how to tell if your property needs one.
What Does AWTS Stand For?
AWTS stands for Aerated Wastewater Treatment System. You’ll also see the terms “aerobic treatment unit” (ATU) and “secondary treatment system” used for very similar technology. In most residential contexts, AWTS and ATU describe the same category of system, just using different regional or manufacturer terminology. NSW Health regulates AWTS installation and servicing as part of its on-site sewage management guidance.
How an AWTS Actually Works
Most AWTS units follow a similar sequence, even though the exact hardware varies by manufacturer:
- Primary treatment: wastewater enters the tank and solids settle out, similar to a standard septic tank.
- Aeration: a pump or blower injects air into the wastewater, encouraging the growth of aerobic bacteria that break down waste far more effectively than the anaerobic process in a standard tank.
- Clarification: treated water settles again, separating any remaining solids before the next stage.
- Disinfection: most systems disinfect the treated water (commonly via chlorine or UV) before it leaves the tank.
- Irrigation: the treated, disinfected water is pumped out to an irrigation area, typically via sub-surface or spray irrigation across your garden, rather than a buried trench.
The result is water treated to a much higher standard than a standard septic tank produces, which is why AWTS effluent can be irrigated across a lawn or garden area rather than confined to a trench.
AWTS vs ATU vs Standard Septic Tank: What’s the Difference?
“ATU” and “AWTS” are, for almost all practical residential purposes, the same thing described two different ways — both use aeration and bacteria to actively treat wastewater on-site. The real comparison homeowners need to make is between this category of active system (AWTS/ATU) and a standard passive septic tank.
| Standard Septic Tank | AWTS / ATU | |
| How it treats waste | Passive settling; soil does most of the final treatment | Active aeration + bacteria + usually disinfection |
| Site requirements | Needs good soil permeability and trench space | Suits smaller, tighter or poorer-soil blocks |
| Moving parts | None | Pump(s) and/or blower, sometimes a disinfection unit |
| Servicing | Periodic pump-out only | Regular servicing required (typically every 3–6 months) |
| Upfront cost | Lower | Higher |
| Effluent disposal | Sub-surface trench | Often, surface or sub-surface irrigation across a garden area |
Signs Your Property Might Need an AWTS Rather Than a Standard Septic
- Your block is smaller or more tightly constrained than what a trench system needs
- Soil testing shows poor permeability or reactive clay
- Your property is close to a waterway, drainage line, or environmentally sensitive area
- You want to reuse treated water for garden irrigation
- Council has indicated a standard system won’t be approved for your site
This isn’t something to guess at, it comes down to a proper soil test and site assessment, which is the first step in any installation we do.
Common AWTS Brands and System Names You Might See
Australian AWTS installations use a range of manufacturers and product lines; names like Taylex and Biocycle are common examples you’ll see referenced in product literature and council approvals across NSW. Each brand has its own servicing schedule and parts, which is one reason it matters that whoever services your system is genuinely set up to work across multiple manufacturers, rather than pushing you toward whichever one they happen to stock.
What Does AWTS Servicing Actually Involve?
Because an AWTS has moving and electrical parts, pumps, blowers, and sometimes UV or chlorine dosing, most councils require regular servicing (commonly every 3 months in the first year, then according to your system’s approval conditions) by a licensed contractor. A typical service includes checking the aeration and pump components, testing effluent quality, checking alarms and electrical connections, and topping up chlorine where relevant. Skipping servicing isn’t just a compliance risk, it’s usually what leads to the alarm going off and an emergency call-out down the track.
How Much Does an AWTS Cost in Australia?
Costs vary a lot by site, system size, and manufacturer, but based on published Australian wastewater pricing guides, the general ranges homeowners can expect are:
- New AWTS installation: roughly $11,000–$25,000, depending on system type and whether disposal is surface or sub-surface
- Changeover from an existing septic tank to an AWTS: roughly $22,000–$30,000, reflecting the extra excavation and decommissioning work involved
- Annual servicing: roughly $300–$550 per year for a standard domestic contract (most councils require at least 2–4 services annually)
- Running costs: modest, typically in the order of a few hundred dollars a year in electricity for the pump/blower
- Component replacement: pumps and aerators typically last around 5 years each before needing replacement
These are general industry figures, not a quote; the right number for your property depends on your soil, block size, site access, and which system suits your council’s requirements. We’d always rather give you an accurate number based on an actual site visit than a generic range.
Making the Right Choice for Your Property
Choosing and installing an Aerated Wastewater Treatment System is a significant investment, but for many modern, tricky, or environmentally sensitive blocks, it is the absolute best way to ensure safe, council-approved waste management. While the upfront costs and regular servicing requirements are higher than those of a traditional passive septic tank, the payoff is a highly efficient system that protects your property and allows you to safely reuse treated water on your gardens.
Because an AWTS relies on a complex mix of underground plumbing and active electrical components, like pumps, blowers, and alarms, the installation and ongoing maintenance usually require hiring multiple different contractors.
That is where we do things differently. Unlike most wastewater providers, our team includes both licensed plumbers and qualified electricians. We handle the entire process, from the initial site excavation and pipework to the electrical hookups and ongoing quarterly servicing, completely in-house. You won’t have to coordinate between different trades or deal with finger-pointing if a component needs troubleshooting down the track.
Whether you are building a new home, upgrading an aging or failing older system, or just need a reliable team to take over your mandatory quarterly compliance servicing, we have you covered.
Not sure if your property needs an AWTS or a standard system? Get in touch with our team today for a free site assessment. We are the preferred installation and service agents for major brands across the Mid North Coast, offering you a seamless, all-in-one solution from day one.
Frequently Asked Questions
What does AWTS stand for?
Aerated Wastewater Treatment System, an on-site system that actively treats wastewater using aeration, bacteria and usually disinfection, rather than relying mainly on the soil.
Is an AWTS the same as an ATU?
For almost all residential purposes, yes, “ATU” (aerobic treatment unit) and “AWTS” describe the same category of technology, just using different regional or manufacturer terminology.
Is an AWTS better than a standard septic tank?
Neither is universally better; it depends on your soil, block size, and council requirements. An AWTS suits smaller or more constrained sites; a standard system is simpler and cheaper where soil and space allow it.
How much does an AWTS cost to install in Australia?
New installations generally run from around $11,000 to $25,000, with a full changeover from an existing septic tank typically higher, at $22,000–$30,000, depending on site conditions. Get a site-specific quote for an accurate figure.
How often does an AWTS need servicing?
Most councils require servicing at least every 3–6 months, though this varies by system and approval conditions. Your service agreement will set out exactly what’s required for your system.
Can I install or service an AWTS myself?
No, AWTS installation and servicing needs to be carried out by a licensed contractor, and most manufacturers require servicing by an approved agent to keep the warranty valid.
Not sure if your property needs an AWTS or a standard system? Get in touch for a free site assessment. We’re a preferred install and service agent for several major AWTS manufacturers across the Mid North Coast.