Installing a new septic system in the Port Macquarie Hastings region in 2026 costs anywhere from $9,000 for a basic conventional system on a rural block with easy access, to $35,000+ for a complex AWTS installation on a constrained coastal site with engineering requirements.
The difference is real and it matters. This guide breaks down every cost component so you can understand what you’re being quoted, know which items are fixed and which have room to move, and avoid getting surprised mid-project.
The Two Main System Types and Their Cost Profiles
1. Conventional Septic Tank + Absorption Trench
The conventional approach: a tank (concrete or poly) receives all wastewater, provides primary treatment, and effluent flows by gravity to a buried absorption trench system in the yard.
Best for: Larger rural lots around Wauchope, Comboyne, and King Creek with good soils, adequate setbacks, and no proximity to sensitive waterways.
Total installed cost range: $9,000 to $18,000
2. AWTS (Aerated Wastewater Treatment System) + Drip Irrigation
An AWTS provides secondary treatment (with disinfection), and the treated effluent is pump-dosed to a subsurface drip irrigation area. Required on constrained sites, coastal locations, and near sensitive waterways.
Best for: Coastal properties (Lake Cathie, Bonny Hills, Camden Haven), smaller lots, sites near waterways, and properties where higher effluent quality is required by Council.
Total installed cost range: $18,000 to $35,000
Complete Cost Breakdown: Every Line Item
Site Assessment and Design ($800 to $2,500)
The site assessment includes percolation testing and a written report specifying what system type is required and what size land application area the soil can support. This is done by a qualified environmental consultant or hydraulic engineer and is a mandatory input to the DA. See our site assessment guide.
Council Development Application ($1,500 to $3,500)
Preparation and lodgement of the DA including the site plan, site assessment report, system specifications, and DA form. Cost includes the Council lodgement fee ($300 to $600) plus any consultant preparation fees. DA processing takes 20-40 business days in the Port Macquarie Hastings LGA.
Construction Certificate ($400 to $800)
After DA approval, a Construction Certificate is required before any physical work begins. This can be issued by Council or a private accredited certifier.
Supply of Treatment System Unit
| System Type | Supply Cost (2026 AUD) |
|---|---|
| Concrete tank, 3,000 L | $1,200 to $2,000 |
| Poly tank, 3,000 L | $1,400 to $2,200 |
| Poly tank, 4,500 L | $1,800 to $3,000 |
| Poly tank, 6,000 L | $2,500 to $4,000 |
| AWTS unit, compact residential | $6,500 to $10,000 |
| AWTS unit, large / premium | $10,000 to $16,000 |
| Biofilter/textile filter system | $7,000 to $12,000 |
Delivery of concrete or large poly tanks to rural areas around Comboyne and Upper Hastings adds $300 to $800 in transport costs.
Earthworks and Tank Installation ($1,500 to $5,000)
Excavation for the tank pit, tank installation including levelling, backfill compaction, and reinstatement of the surface. Cost is heavily influenced by soil conditions:
- Sandy or loamy soil (easy to excavate): $1,500 to $2,500
- Clay or rocky ground (slower, harder): $2,500 to $5,000
- Remote rural site with difficult access: add 15-25% to base costs
Land Application Area Installation
Conventional Absorption Trench ($80 to $150 per linear metre)
Includes excavation, gravel bed, perforated pipe, inspection ports, and backfill. A typical 3-bedroom system on Class 3 soil requires approximately 70 m primary + 70 m reserve = 140 m total.
140 m × $110/m average = $15,400 for the trench system alone.
This is often the most expensive single component of a conventional septic installation and is why total costs can reach $15,000 to $18,000 even with a relatively inexpensive tank.
Drip Irrigation System for AWTS ($3,500 to $7,000)
Includes subsurface drip lines, emitters, manifold, pump chamber, pressure regulators, and filtration unit. The drip field itself has a smaller physical footprint than absorption trenches but the supporting infrastructure (pump, controller, pressure testing) adds cost.
Pump and Dosing System ($800 to $2,500)
Required for AWTS systems and for any conventional system where the land application area is uphill from the tank. Includes submersible dosing pump, controller, alarm, and cabling.
Electrical Connection ($400 to $1,200)
Licensed electrician to install 240V connection to AWTS unit and control panel. Required for all AWTS installations.
Inspection Fees ($300 to $800)
The certifying authority inspects the installation at the required stages (pre-backfill and final). Fee depends on whether you use Council or a private certifier.
Licensed Plumber Labour ($2,000 to $5,000)
The licensed plumber and drainer’s time for connecting inlet and outlet pipes, testing the system, commissioning the AWTS unit, and completing the plumbing notification.
Site Restoration ($400 to $1,000)
Topsoil, seeding or turf over disturbed areas, erosion control around newly installed drip irrigation areas.
Total Cost Summary
| Scenario | Total Range |
|---|---|
| Conventional septic, simple rural lot (Wauchope/Comboyne area) | $9,000 to $15,000 |
| Conventional septic, medium difficulty (most rural-residential lots) | $12,000 to $18,000 |
| AWTS, coastal or constrained site (Lake Cathie, Bonny Hills) | $18,000 to $28,000 |
| AWTS, complex site with engineering (near waterway, engineered fill) | $25,000 to $35,000 |
| Biofilter system, standard residential | $17,000 to $27,000 |
Regional Cost Factors on the Mid North Coast
Coastal location premium: Coastal sites around Lake Cathie and Bonny Hills almost universally require AWTS, adding $8,000 to $12,000 to a base conventional system cost. This is a regulatory requirement, not a contractor choice.
Rural access costs: Sites around Comboyne plateau, Byabarra, or Upper Hastings locations may have travel time and equipment transport costs that add 10-20% to quoted prices compared to sites near Port Macquarie.
Supply lead times: AWTS units are manufactured items. Allow 2-4 weeks lead time for delivery in the Mid North Coast region. Concrete tanks can often be sourced faster from local precasters.
Wet season timing: Installation in the wet season (November, April) can add cost due to slower excavation in saturated ground, soil erosion control requirements, and potential delays from weather events. Where possible, plan installation in the dry season (May, October).
How to Keep Costs Down
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Commission the site assessment early: A poor or rushed site assessment leads to a system design that may need to be re-engineered after lodgement, wasting time and money.
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Get three quotes: Prices for the same work vary between contractors. Three quotes gives you a competitive spread.
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Choose a contractor experienced in Council approvals: An experienced local contractor who knows Port Macquarie Hastings Council’s requirements will avoid avoidable DA delays.
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Don’t overbuild: If your site supports a conventional system, don’t install an AWTS “just in case.” Only upgrade to AWTS if the site conditions or Council requirements mandate it.
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Combine with other ground works: If you are also building a new dwelling or extending, coordinating the septic installation with other earthworks can reduce mobilisation costs.
FAQ
Can I get a ballpark quote without a site assessment? Yes, but it’s a very rough ballpark. Until the site assessment confirms which system type is needed and how large the land application area must be, a precise quote is not possible. Most experienced contractors will give you a range based on property details and system type, with a final quote after the site assessment.
Does the DA cost differ if I use a private certifier vs Council? The DA must still be lodged with Port Macquarie Hastings Council regardless. A private accredited certifier issues the Construction Certificate (CC), which can sometimes be faster than Council. The CC cost is roughly similar between Council and private certifiers. The DA fee is the same.
Is there GST on top of the quoted price? Yes, all quoted prices from registered contractors include or are subject to GST. Confirm whether quotes are GST-inclusive or exclusive. The prices in this guide are indicative and inclusive of GST.
How do I know if I need a conventional or AWTS system before spending money on an assessment? A qualified contractor can often give you a strong preliminary indication based on your property location, lot size, and any obvious constraints (proximity to lake, river, or dam). Contact us for a preliminary discussion before commissioning an assessment.
What’s included in an “installed” price? Always check whether a quoted “installed” price includes the DA, site assessment, all earthworks, the tank, land application area, and electrical connection, or whether it is just the tank supply and installation. Apples-to-apples comparison requires knowing what each quote covers.
Planning a new septic installation in the Port Macquarie or Hastings region? Request a quote; the guides on this site walk through system selection and the approval process, and an inspection is the practical first step.