Installing a septic system in QLD

by | Mar 8, 2023 | Advice & inspiration, Building basics & regulations, Building tips

Though a septic system is hardly the most exciting addition to your new home, it’s an important feature in many homes. But do you need one for your new home? What’s involved in choosing the right septic tank and what regulations do you need to follow? We’ll answer all these questions and more in today’s blog.

Do I need a septic system for my new home build?

Septic systems are installed on a property to handle wastewater and sewage. Whether you’ll need to have one will depend on whether you have access to your area’s sewage system. Most urban places will have access to their local council’s sewerage system, however, this isn’t a guarantee, especially in new developments, so always double-check when buying land.

The need for a septic system is most common in rural and coastal areas due to them being less likely to be close enough to any town sewerage facilities. Either way, it’s best to find out whether you’ll need a septic tank BEFORE you buy a block of land, rather than after.

How close can you build to a septic tank?

The exact distance you can build from a septic tank will vary depending on your region. You should install your system away from your home and never under any building, as this makes it difficult to access and maintain.

Types of Septic Systems

There are many different types of septic systems, so let’s take a closer look at some of the most popular system markets and see which might be the best choice for you.

Primary System

Older systems are often primary systems, and they tend to be the cheapest and simplest version of a septic tank available. However, councils rarely approve these types of systems anymore, as they’re not environmentally friendly and have poor effluent. Because of these issues, the council won’t usually allow these types of tanks on smaller blocks or anywhere considered environmentally sensitive.

Secondary Systems

Sand filter systems

These systems are for a larger site, as you’ll need more space. The system consists of a septic tank, sand filter, subsurface irrigation and absorption trenches. They need to be serviced annually and de-sludged every 3-5 years to ensure optimal performance and longevity.

Composting system – worm farm

An eco-friendly option that is simple to set up. The system pumps site sewage directly into a worm colony that’ll eat through the bacteria. You’ll need to service your system six months after installation and then every two years or so after.

Aerated wastewater treatment systems

This is the most popular system in Australia, due to its versatility. It can be used on narrow lots and sloping blocks, which is great news for anyone with a challenging lot. The system consists of multiple tanks or a large tank with multiple chambers, including an aeration chamber. In terms of maintenance, you will need to service an AWTS quarterly and have someone de-sludge the tank every 3-5 years for optimal performance.

Approvals needed and government legislation around septic tanks

Installing a septic system can have an impact on the environment and the stability of your land, so you’ll need to receive approval before you can go ahead with the installation.

The Queensland Plumbing and Wastewater Code guidelines specify you need to consider the following requirements before installing a septic system:

Environment Protection (Water) Policy 1997: this involves taking reasonable measures to minimise and prevent negative environmental impact.

Environment Protection Act 1994: When your local government inspect your proposal, they’ll weigh up the on-site impact of your septic tank on your soil and the surrounding environment.

Design regulations of septic systems in QLD

The are some regulations you’ll need to ensure you’re in accordance with:

  • It’s the right size and suitable to handle the hydraulic and organic matter and sewage needs of the property.
  • The treatment method will produce effluent that meets the necessary criteria for wastewater.
  • The tank won’t be subject to external or internal loads, ground movements or weather conditions that could cause sewer leakages.
  • Neighbouring ground must be sloping away from the tank. This will help prevent water from entering from the top.
  • All components of the system are accessible and aren’t covered by concrete, asphalt or any material that would impede access.

It’s illegal to empty or dispose of water from a septic tank into a stormwater drain, watercourse, roadside gutter or anywhere that could affect public health.

Ongoing care and maintenance considerations of your septic system

Maintaining and servicing your septic tank will make sure it works more effectively and have a longer lifespan. Here are some steps you can take to keep your septic tank in tip-top condition:

  • Have your septic tank pumped every 3-5 years. This stops sludge building up and building up and overflowing into disposal trenches.
  • Have your grease trap pumped out every 3 months.
  • Pump out grey water every 6-12 months
  • Only have a licensed service agent, or authorised person work on your septic tank.
  • Never turn off the power to your system.
  • Don’t allow any pets, children or living things to consume the wastewater and don’t use it to water any edible plants with it.
  • Don’t cover your disposal outlets with concrete, asphalt or anything that will impede function or access. Grass is your best option as it helps prevent moisture build-up which can lead to erosion.

Quick tips to ensure you remain compliant

  • Make sure to get council approval to install your septic tank.
  • Check any septic tank regulations in your area. This includes any rules when it comes to disposing of greywater.
  • Before purchasing a vacant lot, talk to a builder about what the installation costs will likely be.
  • Installing a septic tank is too big for a DIY project, so hire a professional unless you’ve got some qualifications.

Talk to an experienced building broker

Building a house is a big project made up of many smaller jobs. At Buildi, we can help through the entire building process, from due diligence to choosing a builder. From there, we can help hold your builder accountable while maintaining a good relationship. We’ve managed to save past clients thousands of dollars and over fifty hours worth of work. Get in touch for a free consult and we’ll let you know how we can help you.

Book your free, impartial consultation today!


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Knockdown Rebuild

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