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On-site wastewater management systems (commonly known as septic tank systems) are used on residential, community and business premises. They treat, then recycle or dispose of:

  • greywater, which comes from showers, baths, hand basins, washing machines, laundry troughs and kitchens
  • blackwater, which is toilet waste (from water-flush, incineration or dry composting systems)
  • sewage, which is combined greywater and blackwater.

On-site wastewater management systems must perform effectively and be well managed to minimise risks to public health and the environment. The requirements on them depend on the source of the wastewater, site constraints, treatment method and the quality of effluent needed for the end uses of the treated water:

  • Wastewater treated to primary quality is only suitable for disposal below ground via soil absorption trenches, mounds and evapo-transpiration beds or trenches.
  • Wastewater treated to secondary quality can also be dispersed to land via pressure-compensating subsurface irrigation.
  • Greywater treated to advanced-secondary quality can be used in the home for flushing toilets and in washing machines. It can also be used for surface and subsurface irrigation.

Permit for constructing, installing or altering an OWMS not exceeding 5000L per day

A permit from council is required to construct, install or alter an OWMS with a design or actual flow rate of sewage not more than 5000L on any day.

Systems that can treat more than 5000L per day need an EPA development licence and operating licence (unless an exemption applies).

Assessment standards for on-site wastewater treatment plants

Under the Environment Protection Act 2017 (the Act), an on-site wastewater treatment plant must meet the appropriate standard set by EPA. ‘Appropriate stqndard’ is defined in regulation 4 of the Environmental Protection Regulations 2021.

An on-site wastewater treatment plant type must be assessed by a body accredited under the Joint Accreditation System of Australia and New Zealand or any other accreditation body approved by the Authority (assessment body). The assessment body must certify the treatment plant as conforming with the relevant Australian and New Zealand standard (appropriate standard):

  • AS/NZS 1546.1: 2008, On-site domestic wastewater treatment units, Part 1: Septic tanks
  • AS/NZS 1546.2: 2008, On-site domestic wastewater treatment units, Part 2: Waterless composting toilets
  • AS 1546.3:2017, On-site domestic wastewater treatment units, Part 3: Secondary treatment systems
  • AS 1546.4:2016 On-site domestic wastewater treatment units, Part 4: Domestic greywater treatment systems

Transitional arrangements will also apply to previously issued certificates of conformity that had not expired by 1 July 2021.

The following table summarises the ‘appropriate standards’ and ‘transitional arrangements’ for different types of treatment plants:

Types of on-site wastewater treatment plants Transitional arrangements for previously issued certificates that have not expired at 1 July 2021 Appropriate standard from 1 July 2021
Septic tanks (and vermiculture systems) Certificates issued against AS/NZS 1546.1 2008 will continue to be valid until they expire. AS/NZS 1546.1: 2008, onsite domestic wastewater treatment units, Part 1: Septic tanks.
Waterless composting toilets

Certificates issued against AS/NZS 1546.2 2008 will continue to be valid until they expire.

AS/NZS 1546.2: 2008, onsite domestic wastewater treatment units, Part 2: Waterless composting toilets.
Secondary treatment systems

Certificates issued against AS 1546.3:2017 will continue to be valid until they expire.

Certificates issued against AS/NZS 1546.3:2008 will continue to be valid for 2 years from commencement (that is, to 30 June 2023), or earlier if the expiry date in the certificate is earlier.

AS 1546.3:2017, onsite domestic wastewater treatment units, Part 3: Secondary treatment systems
 Sand filter treatment plants

Section 459 exemption application (see below).

AS 1546.3:2017, onsite domestic wastewater treatment units, Part 3: Secondary treatment systems
(Note: Sand filters will no longer be assessed by councils against the interim standards for sand filters under the Code of Practice – onsite wastewater management publication 891). 
 Domestic graywater systems Certificates issued against AS 1546.4 2016 will continue to be valid until they expire.

Certificates issued against NSW Health: Domestic Greywater Treatment Systems Accreditation Guidelines February 2005 that do not expire by 1 July 2021 will continue to be valid until the date of expiry on the certificate.

AS 1546.4:2016 onsite domestic wastewater treatment units, Part 4: Domestic greywater treatment systems.

(Note: AS 1546.4:2016 was adopted in the legislative framework on 21 November 2016).

Please note that, in highly exceptional circumstances relating to innovative on-site wastewater treatment plants, an exemption from these requirements may be granted to a permit applicant by EPA under section 459 of the Act.

EPA collates certificates of conformity and maintains a list of certificate holders against each treatment plant type.

Transitional approach for sand filter treatment plants – Section 459 exemption pathway

Under the Environment Protection Act 2017 (the Act), councils assess permit applications to construct, install or alter an on-site wastewater management system (OWMS) with a design or actual flow rate of sewage not exceeding 5000L on any day (A20 permit). More information on this role is available in publication 1974.

Councils can only issue A20 permits where the proposed on-site wastewater treatment plant (treatment plant) is of a type approved by EPA. EPA requires treatment plants to meet relevant Australian standards set out in the Environment Protection Regulations 2021 (the Regulations).

A new Australian Standard for secondary treatment systems (STS) was published by Standards Australia in 2017 – Australian Standard AS 1546.3:2017: On-site domestic wastewater treatment units, Part 3: Secondary treatment systems (2017 Standard). EPA communicated to councils, manufacturers and on the EPA website that this would commence 1 July 2021 in line with the Act.

EPA continues to support the importance of meeting requirements in the 2017 Standard for STS and we have actively communicated the intention to transition to the 2017 Standard for three years.

The 2017 Standard applies to all types of STS, including sand filters used as STS (sand filter treatment plant) and aerated wastewater treatment systems.

In June 2021, councils raised concerns with EPA that some sectors of the OWMS industry that designed and installed sand filter treatment plants were unaware of the transition to the 2017 Standard and were not able to obtain a certificate of conformity as required by the Regulations in time for commencement of the Act. Councils also stated that it was impractical for some types of sand filter treatment plants to obtain a certificate of conformity prior to application, as they varied from site to site and were designed for specific conditions.

Councils have requested a transitional arrangement to enable local government and EPA to work together to address this issue.

We acknowledge concerns raised by councils and have developed a streamlined process to support exemptions from the certificate of conformity requirement while we reassess the framework.

Councils can assist applicants to apply for an exemption from the requirement for a certificate of conformity through the following process.

How to submit an A20 application and s459 exemption application

  1. The applicant submits both the A20 application and exemption application to council.
  2. Council submits the exemption application to EPA at permissions@epa.vic.gov.au on behalf of the applicant, with all attachments and evidence required.
  3. EPA must determine the exemption within 15 business days of receipt. EPA must be satisfied that:
    • the exemption won’t pose a risk of harm to health or the environment
    • it isn’t practicable for the applicant to comply with the requirement to provide a CoC

    These EPA exemptions will be valid on the condition that the proposed sand filter treatment plant is assessed by a council to comply with Appendix G: Sand filters of the code of practice – onsite wastewater management (publication 891)

  4. Once EPA informs council of the decision on an exemption, council may begin to deal with the A20 application. Council must not start processing the application until the EPA exemption has been received or a CoC provided.

EPA has developed a form for councils to use to support this process for proposed sand filter treatment systems. EPA will waive the prescribed fee for this application for exemption from a provision of the Regulations.

Councils must not start processing the application until the EPA exemption has been received. To satisfy their notification requirements in section 50(2) of the Act, councils can use the following text to inform applicants of this process:

For the purposes of section 50(2)(b) of the Environment Protection Act 2017, please be advised that your permit application for an on-site wastewater treatment system that includes a sand filter treatment plant will not be complete until such time as EPA has granted an exemption under section 459 of that Act from providing a certificate of conformity. Council will submit your section 459 exemption application to EPA on your behalf. EPA must make a decision to grant or refuse the exemption application within 15 days of receipt. If EPA grant the exemption, Council has 42 days to assess your complete permit application.

Councils continue to have obligations under the Act when assessing permits – importantly, they must refuse to issue a permit if they consider the activity in the application poses an unacceptable risk of harm to human health or the environment.

While this transitional approach is in place, EPA will continue to assess the framework and consider longer-term solutions.

If you have any questions please contact contact@epa.vic.gov.au or call 1300 372 842 (1300 EPA VIC).

Guidance on on-site wastewater management

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Reviewed 22 July 2021