On Site Waste Water

What is an on-site sewage management system?

An on-site sewage management system is the process used to treat domestic sewage and may include a septic tank, an aerated waste treatment system or composting system.  The treated product, being referred to as effluent, is then gravity-fed or pumped to an effluent disposal area.  The effluent is disposed of either by direct absorption into the land, irrigated onto the land or directed to a holding well to be collected by a tanker.

If you are proposing to build on land that cannot be connected to a reticulated sewerage system it will be necessary for you install an on-site sewage management system.  This is likely to be the case if you are building outside of Windsor, South Windsor, Richmond, North Richmond, McGraths Hill, Wilberforce, Glossodia, Freemans Reach, Agnes Banks, Bligh Park, McGraths Hill, Hobartville, Pitt Town or in rural areas and outlying townships.

The on-site sewage management system must be designed, operated and maintained in a manner that will:

  • prevent public health risk;
  • prevent environmental damage (particularly to land, soil, groundwater and surface waters);
  • protect community amenity (e.g. odours).

It is also important that an on-site sewage management system is designed, installed and operated so that it works well into the future.

What type of system do I install?

There is no specific requirement to install any particular type of on-site sewage management system.  The type of system that will be most suitable for your property will depend on a number of factors.  Site characteristics including soil type, soil depth, slope, proximity to water and water balance will determine the most appropriate type of on-site sewage management system for your land.

How do I make an application to install an on-site sewage management facility?

If you are installing a new system, an approval to install must be obtained from Council by submitting an application to Install an On-site Sewage Management Facility.  This application must be submitted to Council prior to commissioning or moving into your new home.  The system must be inspected by Council before you can occupy your house to ensure that it has been installed correctly.

The details accompanying the application are to be site specific and must address the ability of the land to adequately dispose of effluent.

For a domestic system the whole on-site sewage management system must comply with Australian/New Zealand Standard 1547:2012 – On-site domestic wastewater management.

In order to demonstrate that the system is suitable the following information is required to be provided:


Plans drawn to a scale of either 1:100 or 1:200 detailing the following information:

  • the location of the proposed building on the site and identification of the proposed effluent disposal area/s;
  • the sewage management facility proposed to be installed or constructed on the site;
  • any related effluent disposal areas;
  • location of any boreholes;
  • any buildings or facilities existing on, and any environmentally sensitive areas of land, located within 100 metres of the sewage management facility or associated effluent disposal areas;
  • any related drainage lines or pipework (being either natural or constructed);
  • the location of any existing sewage management facility and effluent disposal area (if applicable);
  • contour plan of the land.


The application is to include full specifications of the sewage management facility to be installed or constructed on the site.  This must include a full copy of any certificate of accreditation and associated conditions.

Site assessment

The site assessment is to have regard to topography, soil composition and vegetation of any related effluent application areas.

Effluent disposal area

Calculations are to be provided confirming the adequacy of the disposal area.

Geotechnical Report

A geotechnical report will only be required after an initial assessment of the application identifies that the proposal has a high risk due to site conditions and/or proposed volume of effluent generated by the proposal.

Note: An 'Approval to Operate a System of Sewage Management' must also be issued by Council prior to commissioning the system or occupying the development.  The installation must be inspected by Council before occupation to ensure that it has been installed correctly.  An 'Approval to Operate' will be issued following a satisfactory inspection of the system.

More information:

For information relating to the requirements relating to on-site wastewater disposal please refer to Chapter 7 Effluent Disposal in Part C of Council’s DCP.

Local Government (General) Regulation 2005

Environment and Health Protection Guidelines – On-site Sewage Management for Single Households

If you would like further information about on-site sewage management please contact Council’s Sewage Management Facility Team on (02) 4560 4444 or via email: council@hawkesbury.nsw.gov.au

Page ID: 63889