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Septic tank applications

If a sewer is not available for waste and wastewater disposal, you must install a septic tank.

Installing a septic tank

You must install a septic tank under the:

  • the Environmental Protection Act 1970
  • Septic Tanks Code Of Practice.

You must apply if you want to install or alter a pre-existing septic system.

How to apply

To apply for a septic system permit, download and complete the application form.

Download the application form

You can submit your application by email, mail or in person:

  • email [email protected]
  • mail it to Knox City Council, 511 Burwood Highway, Wantirna South VIC 3152
  • submit it in person at the Knox Customer Service Counter located at our council offices at 511 Burwood Highway, Wantirna South VIC 3152


The application fee is $798.

This fee is current from 1 July 2024 to 30 June 2025.

The importance of septic tanks

Septic tanks are sealed round or rectangular containers that break down sewage and wastewater.

Septic tanks treat, then recycle or dispose of:

  • sewage, which is combined greywater and blackwater
  • greywater, which comes from showers, baths, hand basins, washing machines, laundry troughs and kitchens
  • blackwater, which is toilet waste
  • organic waste.

Septic tanks are used on residential, community and business premises.

Need help?

Contact us and we will get back to you.

Or call our City Safety and Health team on 9298 8000.

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