Supply-only vs fully installed price
The single biggest decision driving total cost is whether you buy the tank supply-only and engage your own licensed plumber, or buy a "fully installed" package from a plumbing trade business. Supply-only pricing strips out installation margin, showroom overheads, and the trade markup typically applied to bundled tanks. For a 1500L tank in a typical install, supply-only sourcing saves $400–$1,500 on the tank line item alone.
The flipside: you coordinate the licensed plumber, excavator and council application yourself (or rely on your builder to do it). For most owner-builders and rural buyers this is straightforward — the plumber you'd hire either way handles the regulatory side. See supply-only vs full-service septic tanks for the full breakdown.
Freight and pickup pricing by region
Bush Billabongs is supply-only with pickup from our location at no charge. Freight to a delivery address is quoted by postcode. Indicative freight bands for a 1500L poly tank (61 kg):
- Northern Rivers NSW (Lismore, Byron, Ballina, Tweed): ~$150–$300
- Sydney metro and 100km radius: ~$180–$350
- Central West NSW (Cowra, Bathurst, Orange, Dubbo): ~$220–$420
- Sunshine Coast / Noosa region QLD: ~$200–$380
- Brisbane metro QLD: ~$220–$400
- Melbourne metro / regional VIC: ~$300–$550
Concrete equivalent freight runs 3–6× higher because of weight and HIAB requirements. This is one of the strongest single arguments for poly over concrete on rural deliveries.
Ongoing cost — pump-outs and inspections
Once installed, the running costs of a conventional septic system are low:
- Pump-out every 3–5 years: $250–$500 for a 1500L tank
- OSSM annual registration (NSW/QLD): $40–$150/year
- 5-yearly re-inspection (NSW): $80–$200
- VIC EPA permit renewal: varies by council
No electrical components, no filter replacements, no service contracts. An AWTS by comparison requires quarterly servicing at $300–$500/year plus electricity, which dwarfs septic running costs over a 20-year horizon.
Frequently asked questions
What is the cheapest septic tank in Australia?
For a compliant, AS/NZS 1546.1-certified tank, the cheapest option in Australia is a supply-only 1500L polyethylene tank, starting at $949 ex GST. Sub-$900 tanks usually come without proper certification documentation, which means your council application will be rejected.
How much should a septic tank cost in Australia?
Reasonable price ranges: 1500L poly $950–$2,000, 2500L poly $1,800–$3,500, 3000L+ poly $2,500–$5,000, concrete equivalents $1,500–$3,500+. Anything significantly above these ranges usually reflects installation upsell baked into the tank price.
Is GST included in advertised septic tank prices?
Many supply-only providers (us included) quote ex GST because most rural builders register for GST and claim it back. Always confirm whether a quote is ex or inc GST — the 10% difference matters on larger systems.
Why are some septic tanks twice the price of others?
Three reasons: (1) traditional plumbing suppliers bundle installation margin into the tank price, (2) larger tanks (3000L+) need bigger moulds and ship at higher freight cost, (3) AWTS units are a different product class entirely and cost 5–10× more. Within the certified polyethylene septic tank category, the price spread is mostly margin, not material.
Do septic tank prices include delivery?
Usually no. Pickup is generally free at the supplier's depot. Freight to regional addresses is quoted by postcode. For our 1500L tank (61 kg empty) freight typically runs $150–$450 within NSW, QLD and VIC. Concrete tank freight is much higher because of weight.