Chapter B8: On-Site Sewage and Wastewater Management

1 - Introduction

1.1 Scope of this Chapter

This chapter applies to all land within Kempsey local government area that is not capable of being connected to a reticulated sewerage system and development that generates the need for a sewage management system.

This chapter applies to applications for development involving building works and development applications for subdivision.

1.2 Relationship to Other Chapters of this DCP

The provisions contained in Chapters included in Parts C, D, E and F of this DCP override the provisions of this Chapter to the extent of any inconsistency.

1.3 Relationship to other Documents, Policies, Guidelines and Legislation.

This Chapter relates to the Kempsey On-site Sewage Management Strategy (OSMS Strategy) contained in Appendix H2 of this DCP. Details regarding the installation and operation of a sewage management system are outlined in the OSMS Strategy.

The OSMS Strategy refers to the following:

  1. Australian Standards:
    • AS/NZS 1547:2012 - On-site Domestic Wastewater Management; and
    • AS/NZS 3500.5:2000 - National Plumbing and Drainage Domestic Installations.
  2. Guidelines:
    • Environmental & Health Protection Guidelines 1998 - On-site Sewage Management for Single Households;
    • NSW Plumbing and Drainage Code of Practice 2006; and
    • NSW Health - Greywater Reuse in Sewered Single Domestic Premises (April 2000)
  3. State Environmental Planning Policies:
    • The State Environmental Planning Policy 62 (SEPP62).
  4. Legislation:
    • Local Government Act 1993;
    • Local Government (General) Regulation 2005; and
    • Protection of the Environmental Operations Act 1997.

The following Council Policies, or their current equivalent, are relevant to this chapter:

  • Policy No 1.8: On-site Sewerage Management;
  • Policy No 3.2: Sewer Services Policy; and
  • Procedure 3.2.6: Developer Service Charges for Water and Sewer where Allotments are Vacant and park of an Existing Assessment.

A separate approval issued in accordance with the Local Government Act 1993 is required for any of the following:

  • Installation of an OSMS system;
  • Operation of an OSMS system;
  • A Commercial Sewage Management Facility or a Package Wastewater Treatment Plant; or a
  • Greywater treatment system.

Such approvals are required in addition to any development consents issued for development.

2 - Chapter Objectives

The objectives of this chapter are:

  1. To ensure developments are provided with suitable provision to dispose of effluent.
  2. To dispose of effluent in an environmentally safe manner.
  3. To protect surface water, stormwater, waterways, land, vegetation, public health and community amenity from the impacts associated with OSMS systems.
  4. To encourage the re-use of resources (including nutrients, organic matter and water).
  5. To ensure that appropriate measures are adopted should OSMS’s be constructed in flood affected areas.

3 - Development Requirements

It is recognised that not all sites have natural characteristics suitable for on-site disposal of effluent. Excessive slope, flood potential, high ground water and other features may be considered as site limitations when undertaking a site report. In these cases, the site may need to be improved, or an alternative system employed.

3.1 General

Desired Outcomes

DO1 - On-site wastewater disposal is designed and located to have no negative effect on the community and natural environment.

DO2 - Effluent disposal meets the provisions of the Kempsey OSMS Strategy (refer to Appendix H2 of this DCP).

DO3 - All development applications demonstrate that appropriate connection to Council’s sewer system or alternative on-site disposal system may be provided to service the development.

DO4 - On-site sewage management systems:

  • prevent the spread of disease;
  • prevent the spread of foul odours;
  • prevent the contamination of water;
  • prevent degradation of soil and vegetation;
  • discourage insects and vermin;
  • ensure that persons do not come into contact with untreated sewage or effluent (whether partially treated or not) in their ordinary activities on the premises;
  • facilitate the re-use of resources;
  • minimise any adverse impacts on the amenity of the land on which it is installed or constructed and other land in the vicinity of that land; and
  • are sized to accommodate the expected loads.
Development Requirements
  1. The onsite wastewater disposal system is designed to meet the relevant requirements to secure an approval to be issued under Section 68 of the Local Government Act 1993.
  2. Where available, new lots created by subdivision and any new development are to be connected to Council’s reticulated sewer network. Where connection to the sewer system is not available, suitable on-site effluent disposal provisions are to be provided.
  3. For a development application for a new building or other application for a whole new system install, an On-site Sewage Management Assessment Report is to be submitted with the application that:
    1. Is prepared by a suitably qualified consultant;
    2. Complies with the relevant requirements of:
      • AS/NSZ 1547:2012 - On-site Domestic Wastewater Management; and
      • Environmental Health and Protection Guidelines 1998.
    3. Includes a drainage concept plan showing the disposal area; and
    4. Includes a site and soil analysis to inform the design of the disposal area.
  4. For applications involving upgrades to existing OSMS’s (eg. increase in the number of people or due to failure), consult with Council for the need for an On-site Sewage Management Assessment Report or other requirements.
  5. The development proposal demonstrates that the site is suitable for an on-site wastewater disposal system that:
    1. Is located away from flood areas, waterways and water supply;
    2. Prevents pollution from microbial, organic or nutrient sources to soils or receiving waters (including groundwater);
    3. Is supported by an On-site Sewage Management Assessment Report indicating appropriate soils and water table depth for the system;
    4. Causes no spread of disease or risk to public health by micro-organisms;
    5. Does not spread foul odours;
    6. Provides a reserve irrigation area;
    7. Minimises cumulative impacts;
    8. Does not encourage insects/vermin;
    9. Ensures persons do not come into contact with untreated sewage or effluent (whether treated or not) during ordinary activities on the premises;
    10. Minimises adverse impacts on the amenity of the premises and surrounding lands; and
    11. Locating the effluent disposal area downhill from potential/existing home sites.
  6. On-site wastewater treatment systems are not to be located:
    1. Within 100 metres of a waterbody, waterway or wetland;
    2. Within 250 metres of a water supply well or bore;
    3. Within 40m of a dam or intermittent watercourse;
    4. On slopes steeper than 1 in 8 (12%);
    5. Where the treatment facility (ie septic tank) is below the 1 in 100 year flood level;
    6. Where the disposal area is below the 1 in 20 year flood level;
    7. On soils with permeability greater than 3.5m per day;
    8. Within 1 metre of the seasonally high water table or bedrock; and
    9. Where a reserve irrigation area is not available for emergency use.

      Note - Pump-out systems are not acceptable for sewage disposal.
  7. Any proposed greywater diversion systems or greywater treatment systems are to demonstrate that the greywater diversion system and the proposed application and use of diverted greywater, meet the relevant requirements referred to in the Kempsey OSMS Strategy.
  8. The maximum loading on individual treatment system is 2,000 litres per day (equivalent to usage by 10 persons) and the system includes:
    1. Primary treatment (size according to approved manufacturer’s specification);
    2. Sand filtration or equivalent porous material;
    3. A pressurised distribution network;
    4. Sub-surface irrigation;
    5. Has a wet weather storage capacity; and
    6. Soils underlying irrigation areas have a permeability rate of less than 3.5m/per day.
  9. A sewerage disposal system must be in accordance with the relevant provisions of the Local Government (Approvals) Regulation 1999.

    Note - Soils comprising mainly of sand, gravel, fractured rock or heavy clay are not generally acceptable.

3.2 On-site Disposal Area

Desired Outcomes

DO1 - A sufficient area is available for the on-site system and soil conditions are suitable for the system.

Development Requirements


Note - The area required will depend on a variety of site specific conditions, such as soil types and slope, among others. The area is designed so it is non-trafficable by vehicles to prevent soil compaction.

3.3 Strata and Community Title Subdivision

Desired Outcomes

DO1 - In the instance of Strata and Community Title Subdivision, an area is available for a communal on-site system and site conditions are suitable for such a system.

Development Requirements


Note – Will depend on a variety of site specific conditions, such as soil types and slope, among others.