Which wastewater system suits your block?
If your property isn't connected to sewer, wastewater gets treated on your own land — and the right system is rarely a free choice. Your soil, block size, slope, climate and council narrow the field before your budget does. In every state the starting point is a soil and site assessment against AS/NZS 1547:2012, the Australian standard for on-site wastewater management; in Victoria and several other states this takes the form of a formal Land Capability Assessment.
These guides compare every mainstream option honestly — including the ongoing servicing each one locks you into, which is where the real cost differences hide. When you've shortlisted a system, check the approval rules in your state before you sign anything.
| System | How it works | Suits | Installed cost | Maintenance burden |
|---|---|---|---|---|
| Conventional septic | Tank settles solids; effluent soaks away through absorption trenches | Larger blocks with free-draining soil | $8k–$18k | Low — pump-out every 3–5 years |
| AWTS (aerated system) | Multi-chamber tank aerates and disinfects; treated water irrigates the garden | Smaller blocks, poorer soil, reuse on gardens | $12k–$20k | High — mandatory quarterly servicing, runs on power 24/7 |
| Sand / media filter | Septic tank first, then effluent is dosed through a lined sand bed for secondary treatment | Clay soils, high water tables, sensitive sites | $15k–$28k | Moderate — pump-outs plus annual checks, no daily power-hungry blower |
| Composting toilet | Waterless toilet composts solids on-site; greywater still needs its own approved system | Off-grid builds, low water use, difficult sites | $2k–$12k (toilet only; greywater system extra) | Hands-on — regular emptying and compost management |
| Greywater system | Diverts or treats shower/laundry water for garden use; toilets still need a blackwater system | Cutting load on an existing system, drought-proofing gardens | $500–$16k (simple diverter → full treatment) | Low to moderate, depending on diversion vs treatment |
System guides
Septic tanks & trenches
The conventional option: how it works, lifespan, and when it's still the smartest buy.
AWTS — aerated systems
Treated water you can irrigate with, in exchange for power bills and a mandatory service contract.
Sand & media filters
For clay soils and sensitive sites where trenches won't pass the soil test.
Composting toilets
Waterless options, what councils think of them, and why greywater is the catch.
Greywater treatment & reuse
Diversion vs treatment, and what each state allows without a permit.
Brands: Taylex, Fuji Clean & co
The Australian brand landscape, service networks, and why the local agent matters most.
Common questions
Can I choose any system I like?
No — the soil and site assessment and your council narrow the field first. Blocks that fail the soil test for absorption trenches usually become an AWTS-or-sand-filter decision, and some councils mandate secondary treatment near waterways regardless of soil.
Is an AWTS "better" than a septic tank?
It treats effluent to a higher standard, but it costs more to buy, runs on mains power around the clock, has more parts that can fail, and locks you into quarterly servicing. On a big block with good soil, a conventional septic is often the cheaper system over 15 years.
What does the whole process cost, start to finish?
Budget for the site assessment ($600–$2,500), council application fees, the system and installation ($8,000–$28,000 depending on type), plus ongoing servicing. Our cost guides break each piece down.
What happens if I install without approval?
Councils can order rectification or removal at your cost, and unapproved systems surface in pre-purchase inspections when you sell. Every state requires approval before installation — see your state's process.
Not sure which way to go?
Local installers quote against your actual soil, block and council rules — that usually settles the system question fast.