About septic systems

In Casey, the septic systems commonly used are conventional septic tanks and mechanical treatment plants.

A conventional septic tank system comprises of a septic tank and a series of soil absorption and/or transpiration trenches. All wastewater enters the septic tank. The solids settle to the bottom and are retained in the tank, forming a sludge layer, whilst fats and greases collect at the top.

A mechanical treatment plant consists of a large tank with several treatment compartments. The first is like a septic tank, the second mixes air with the wastewater to assist bacteria to break down solids, the third allows for settling of solids and the last disinfects through chlorination. Wastewater from treatment plants is disposed through absorption and/or transpiration trenches, surface and sub surface irrigation.

If you are considering purchasing a new domestic on-site wastewater management system (called a septic system), you need to know about the systems available and how they work. The factsheet Septics and Wastewater Treatment Systems (408kb) will help you to select the right type of system for your property and to get approval from council.

Please complete the Credit Card Authorisation Form (249kb) if you wish to pay for your permit by credit card.

Installation information for installers and property owners

Household septic tank systems - Information for installers (86kb)

Household septic tank system - Information for property owners (84kb)

Installation/Alteration of a septic tank system - Application Form

Installation/Alteration of a Septic Tank System application form (360kb)

Further information

If you need further assistance, please contact the City of Casey's Environmental Health Department.

Further information on septic tanks can be found on the EPA website.