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Guide on how the on-site wastewater treatment Australian Standards updates affect you

In January 2021 updates to the Australian Standards AS1546.3:2017 which govern the use of on-site wastewater treatment systems came into effect in most states across the country, with Queensland to start applying the update in 2024.

The changes to the on-site wastewater system Australian Standards endeavours to create a “contemporary, streamlined and flexible legislative scheme for plumbing and drainage”. However, there are concerns over the costs and system limitations of some of the changes will create.

We’ve put together this guide to help you understand how the updates will affect the on-site wastewater management of your Queensland property in 2024.

Minimum secondary treatment wastewater system capacity requirements

Currently, in Queensland, there is no minimum treatment capacity requirement for secondary wastewater systems.

At the moment property owners can install the treatment unit which caters for the specific wastewater needs for their home. The new standards, however, require that every secondary treatment system installed has a minimum hydraulic capacity of 1,200 litres per day.

This means your choice of secondary wastewater treatment system will be limited to those which cater for these requirements, regardless of whether you need one this size or not.

Need to install or upgrade your on-site system? Speak to your local wastewater specialist to find out what options are available to suit your home wastewater requirements.

Increased costs associated with installation and operation

The base requirement for a larger unit can also affect the costs associated with installing and operating a wastewater treatment system on your property.

Many advanced passive wastewater systems can offer lower operational expenses as they run without the need for external power. These units can be more cost effective to install and operate at low volume sized systems, however, become less so at the higher volumes the new standards require.

Aerated wastewater treatment systems (AWTS) can often be scaled to deal with the higher base volume the standards set, yet this style can have higher ongoing costs due to aspects such as periodic monitoring, testing, reporting, power, and maintenance.

The advantages and disadvantages of both styles need to be considered in relation to your budget and system requirements when choosing which one to install. We recommend you seek advice from a specialist in this area.

Looking to install or upgrade your On-site Sewage Facility? Let our wastewater experts help you.

Reduced options available for smaller sized properties

Due to the increased land area needed for the larger sized 1,200 L/per day AWT or passive system, some units will be unsuitable for smaller properties. As a result this reduces the wastewater treatment options available for many homes on smaller lots.

It is expected that this issue will affect many applications across the country with only 54 of the 4,000+ systems installed since 2011 being over the 1,200 L/per day size.

Potential reduction of industry competition

With a range of small-scale wastewater treatment units no longer useable, many of the minor manufacturers who previously catered for this section of the market will be excluded. This could lead to smaller suppliers being unviable, leaving Australia with reduced competition throughout the industry and fewer options to cater for the huge variety of wastewater requirements in homes across Australia.

When do the wastewater standards changes come into effect in QLD?

The new Australian Standards AS1546.3:2017 will influence on-site wastewater system upgrades & replacements or new systems installations from January 2024.

Need help to make informed decisions as to the ideal on-site wastewater system to suit your home and the upcoming Australian Standard changes? Speak to the experienced team at Express Wastewater Solutions today.

More information on this topic can be found here - Onsite wastewater system Standards update could lead to higher costs

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Guide on how the on-site wastewater treatment Australian Standards updates affect you Let our experts help you.

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    Because we are not a manufacturer and not tied to one particular system we can always offer the best solution for your wastewater needs.


    Because we do this every day we have developed a close knit expert team for every step of the process – from plans and council paperwork to excavations, electrical and plumbing. We handle it all to make the whole process as stress free and quick as possible.


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    Not sure what system is right for you, or want to know if your system is working properly? Just give one of our friendly wastewater experts a call and they will be more than happy to help.


    We will always look to repair your system rather than replace it if it does not need to be, which will generally save large amounts of money sometimes up to and over $10,000.