Nutrient retentive systems

For areas where sewerage is not available, on-site waste water treatment systems (such as septic tank systems and aerobic treatment units) need to be installed to treat the waste water. Properties that are located within sensitive environmental areas will require nutrient retentive systems.

Making an application

An application to construct or install a system for the treatment of waste water must be approved by our Health Services prior to installation, to ensure the system complies with State legislation.

What to include in your application

The application must include:

  • a site plan showing:
    • all existing and proposed structures;
    • the number of plumbing fixtures to be connected into the system;
    • the proposed location for the on-site waste water treatment system; and
    • the location of boundaries, stormwater drains, swimming pools, pathways, driveways and bores (both on the subject lot and the neighbouring lots).
  • the completed application form available from the Department of Health website
  • the prescribed fee:
    • for applications where the on-site waste water treatment system connects to five bedrooms or less the fee is $236; or
    • for applications where the on-site waste water treatment system connects to more than five bedrooms, or if there is more than one system on the property, the application may need to be referred to the Department of Health for approval. These applications incur an additional fee.

Installing the system

After approval has been granted, the plumber can commence installation as per the conditions of approval. Once the system has been installed, the plumber is required to contact our Health Services to arrange for a final inspection.

Please note: The fee for this has been included in the application fee, so no additional payment is required.

At this time we require that:

  • the system has been fully installed
  • both septic tanks have been filled with water to the bottom of the inlet square of each tank at least 24 hours prior to the inspection
  • the bottom of the tanks must be hard
  • the system is to be left uncovered – all lids are to be left off so the Environmental Health Officer can inspect each septic tank (both inlet squares must be visible) and each soak well
  • if leach drains are installed, the first and last section of each leach drain must be exposed
  • the top of the diverter valve must be at ground level
  • an ‘As Constructed’ plan has been completed and is given to the Environmental Health Officer at the time of the inspection if the final inspection does not match the approved plan. The ‘As Constructed’ plan is to include all distances to structures, boundaries, bores etc. If there is significant deviation from the approved plan, the system may not be passed.

Please note that if the above is not undertaken at the time of the final inspection, the system will not be passed. If the system does pass the inspection, we will issue a Permit to Use.

Decommissioning a system

The Water Corporation is installing sewer mains within specific areas of the City of Rockingham as part of the State Government’s Infill Sewer Program.

The availability of sewer mains in your street will mean that your property must be connected within a timeframe specified by the Water Corporation.

When you connect to sewer, you are required to decommission your existing septic tank and effluent disposal system when the following circumstances arise:

  • there is a change of ownership of the property (accordingly the owner has 60 days to decommission the septic tank apparatus)
  • there is a material change in the use of the premises (accordingly the owner has 60 days to decommission the septic tank apparatus)
  • if the foundations for a building on the premises are to be built closer than 1.2m to the septic tank apparatus or a building is to be constructed above the septic tank apparatus or closer than 1.8m to any leach drain or soakwell (accordingly the owner shall decommission the septic tank apparatus before the building work commences).

If you intend to undertake construction within 1.8m of a decommissioned on-site waste water treatment system, the system will need to be removed and not just filled in.

Decommissioning means that:

  • all septic tanks, soakwells and/or leach drains are pumped empty by a licensed liquid waste contractor
  • all empty septic tanks, soakwells and/or leach drains must be either removed or have their lids and bases broken and filled with clean sand.

When an on-site waste water treatment system is decommissioned, notification should be provided to our Health Services team.


Greywater systems recycle the waste water from bathrooms and laundries for use as garden irrigation. Only greywater systems that have been approved by the Executive Director, Public Health may be installed. Installation of a greywater system must be approved by us before installation, and will require a formal application to be made and payment of all relevant fees.

Greywater systems and onsite waste water treatment systems must be located entirely within the property boundary, and are not permitted to be installed on the verge.

For more information on greywater systems please visit the Department of Health website

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