Where Can You Put a Septic Tank or an Aerated Wastewater Treatment System (AWTS)?

Installing a septic tank or an Aerated Wastewater Treatment System (AWTS) isn’t just about digging a hole and dropping in a tank — it’s about following strict Australian regulations and ensuring your system functions safely, efficiently, and in compliance with local council requirements.
Where you put your tank affects treatment performance, environmental safety, property access, and long-term maintenance costs.

This guide walks you through the rules, distances, and site factors you must consider when deciding where to position your septic tank or AWTS.

1. Understanding the Basics

Before we talk about where you can put a septic tank or AWTS, you need to know what they are and why placement matters.

• Septic Tank – A below-ground wastewater system that uses natural bacterial action to treat wastewater. Effluent is usually discharged to a soil absorption area or irrigation field.

• Aerated Wastewater Treatment System (AWTS) – An advanced secondary treatment system that uses mechanical aeration and biological processes to treat wastewater to a higher standard, allowing for safe surface irrigation in many cases.

Placement matters because:

• Incorrect positioning can lead to system failure.

• Poor siting can cause groundwater contamination.

• It may violate council regulations, resulting in fines or forced relocation.

• Access for pumping, servicing, and repairs must be maintained.

2. Australian Standards and Council Regulations

In Australia, AS/NZS 1547:2012 and local council health/environmental regulations govern the installation of on-site wastewater systems.

While rules vary by state and council, most councils require:

• A minimum setback distance from buildings, boundaries, and water sources.

• Compliance with site-and-soil evaluations to determine the most suitable location.

• Access for service vehicles (septic pump-out trucks, AWTS technicians).

In NSW, for example, local councils refer to:

• The Local Government (General) Regulation 2021

• NSW Health On-site Sewage Management Guidelines

• Specific council policies (Hawkesbury, Shoalhaven, Wollondilly, etc.)

3. General Clearance Guidelines

Although each council may have slightly different requirements, here’s a common guide to minimum distances:

Important: Always check with your local council as distances vary.

4. Soil Type and Drainage Considerations

The soil beneath and around your septic or AWTS plays a huge role in determining placement.

Factors assessed during a Site and Soil Evaluation (SSE):

• Soil permeability – Sandy soils drain quickly; clay soils drain slowly.

• Groundwater levels – High water tables can flood tanks and leach fields.

• Slope – Steeper slopes need engineered designs to prevent runoff contamination.

• Flood zones – Avoid installing tanks in areas prone to flooding.

Tip: AWTS systems can work better in sites with poor soils because they produce higher-quality effluent that can be safely irrigated in surface areas.

5. Accessibility for Servicing

Both septic tanks and AWTS need regular maintenance:

• Septic tanks: Pumped every 3–5 years.

• AWTS: Serviced every 3 months (quarterly) with reports sent to council.

Best practice for accessibility:

• Ensure pump trucks can park within 30 m of the tank.

• Keep access clear — no permanent structures over lids.

• Position tanks where heavy equipment won’t damage irrigation areas.

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6. Special Considerations for Septic Tanks

• Below-ground installation only – Must be buried and covered.

• Gravity vs. pump systems – Placement may depend on the ability to achieve natural fall from the house to the tank.

• Drainage field location – Must be downhill or pumped from the tank.

7. Special Considerations for AWTS

• Proximity to power – AWTS require electricity to run aerators and pumps.

• Irrigation area access – Keep in mind sprinkler lines and avoid high-traffic zones.

• Backup in power outage – Ensure tank location allows for emergency bypass or holding.

8. Common Mistakes in Placement

1. Too close to structures – Can undermine building foundations.

2. Too close to boundaries – May breach legal setbacks.

3. On unstable or steep slopes – Leads to erosion or tank movement.

4. In flood-prone areas – Risk of contamination during floods.

5. Over root zones of large trees – Roots can damage tank walls and pipes.

6. Blocking access – Making future servicing difficult or impossible.

9. How to Choose the Best Location

Follow this step-by-step process:

1. Get a Site & Soil Evaluation – Often required by council before approval.

2. Mark key distances – Use a site plan to map buildings, boundaries, watercourses.

3. Plan for future maintenance – Include vehicle access.

4. Consider drainage and irrigation areas – Ensure proper fall and runoff control.

5. Consult your installer and council – Final approval must be obtained before installation.

10. Legal Requirements Across States

Here’s a quick look at typical state-specific guidelines:

• NSW – Must comply with Local Government Act and council-specific OSMS policy.

• QLD – Plumbing and Drainage Act 2018 plus council On-site Sewerage Codes.

• VIC – EPA Code of Practice Onsite Wastewater Management.

• SA – Department for Health On-site Wastewater Systems Code.

• WA – Department of Health Wastewater System Approval Process.

11. Placement Checklist

Before installation, make sure you’ve checked:

• Setback distances meet council rules.

• Tank is above flood levels.

• Soil type supports disposal area.

• Access for service vehicles is planned.

• Irrigation area is away from play areas, pools, and edible gardens.

• Power supply is available for AWTS.

12. Environmental Impact

Poorly placed septic or AWTS tanks can:

• Contaminate groundwater.

• Pollute nearby rivers or creeks.

• Cause odour problems.

• Damage surrounding vegetation.

Correct placement protects both your property and the environment.

13. Working With Professionals

Installing a septic tank or AWTS is not a DIY job — licensed plumbers and council-approved wastewater designers will:

• Assess your land and soil.

• Ensure compliance with all rules.

• Install the system correctly.

• Submit necessary reports to council.

Where you put your septic tank or AWTS is one of the most important decisions you’ll make in the installation process. The right placement means your system will run efficiently for decades, keep your property safe, and meet all environmental and legal obligations.

Always consult with your local council, get a professional site assessment, and choose an installer who understands both the technical and regulatory requirements. 

Call Eco Septic on 1800 808 135 for expert advice when it comes to Wastewater Solutions in Australia