Liquid trade waste

Liquid trade waste is any discharge to a sewerage system other than domestic waste from a hand wash basin, shower, bath or toilet.

Sewerage systems are designed to safely collect, transfer and treat wastewater that is mostly of domestic origin. However, sewerage systems may also accept liquid trade waste discharges provided they are planned and controlled within acceptable limits.

Sound regulation and pricing of sewerage and liquid trade waste is a key component of the NSW BPM of Water Supply and Sewerage Framework ((PDF 23.9 KB)).

Approval to discharge

Approval to discharge

Businesses or government agencies proposing to discharge liquid trade waste to a council sewer must have prior approval from the council responsible for regulating sewerage and trade waste in that area.

For further information, read the fact sheet Protect our environment by managing your liquid trade waste ((PDF 237.5 KB)).

Liquid Trade Waste Regulation Guidelines

To assist local water utilities (LWUs) with best-practice regulation of sewerage and trade waste in regional NSW, the NSW Government has issued the Liquid Trade Waste Regulation Guidelines ((PDF 3.3 MB)).

The Liquid Trade Waste Regulation Guidelines set out the comprehensive NSW framework for the regulation of sewerage and trade waste. The guidelines are driven by the NSW Best-Practice Management of Water Supply and Sewerage Framework and are consistent with the National Wastewater Source Management Guideline, published by the Water Services Association of Australia in July 2012.

The Liquid Trade Waste Regulation Guidelines include Appendix D: Model Policy for Liquid Trade Waste Regulation ((PDF 344.7 KB)). LWUs are required to adopt and implement a liquid trade waste regulation policy in accordance with this model policy.

For a hard copy of the policy, trade waste application forms, and general conditions of approval, contact Haddie Man on (02) 9842 8483. These are also available to LWUs online through the NSW Performance Monitoring Database (login required).

The Liquid Trade Waste Regulation Guidelines simplify LWU approval of trade waste dischargers by:

  • authorising LWUs to assume concurrence for low risk liquid trade waste dischargers
  • encouraging LWUs with significant experience in liquid trade waste regulation to apply for authorisation to assume concurrence for medium risk liquid trade waste dischargers
  • simplifying the approval process for liquid trade waste applications made by government agencies.

By following the guidelines, LWUs can:

  • meet their due diligence obligations and achieve improved environmental outcomes by complying with the LWU's sewage treatment works licences
  • improve sewerage system performance, including reduced frequency of sewer chokes and odour complaints
  • simplify and speed up liquid trade waste approval
  • provide a financial incentive to business and industry for cleaner production and waste minimisation
  • provide cost-effective liquid trade waste services and achieve full cost recovery for non-residential sewerage and trade waste services, and remove existing cross subsidies
  • reduce residential sewerage bills as improved sewerage system performance will free up system capacity and enable the LWU to serve new development and population growth without needing to augment the existing sewerage infrastructure.

The department develops and updates the Liquid Trade Waste Regulation Guidelines, the Model Trade Waste Regulation Policy and related documents. DOI Water also provides its concurrence to the LWU approval of high risk and medium risk dischargers, as well as authorising to suitably qualified LWUs to 'assume concurrence' for medium risk discharges and consenting to LWU trade waste policies.

We assist LWUs by:

  • providing expert advice and technical support on trade waste matters
  • providing training courses in regulation of sewerage and trade waste
  • representing regional NSW on trade waste issues at state and national forums.

Information for plumbers

Plumbing work for liquid trade waste installations must now comply with the Plumbing Code of Australia and Australian Standard AS 3500 Part 2 Sanitary Plumbing and Drainage.

In non-metropolitan areas in NSW, local councils regulate any trade waste discharge to their sewerage systems. Council approval is required under section 68 of the Local Government Act 1993 for any discharge, other than domestic sewage, to the sewerage system.

Council requirements for trade waste discharges into sewerage systems need to be in accordance with the Liquid Trade Waste Regulation Guidelines ((PDF 3.3 MB)).

The guidelines also provide important information for plumbers, including sizing and installation requirements for pre-treatment equipment (see Appendix F 'Overview of common methods of liquid trade waste pre-treatment' on pages 239 to 273 and 288 to 302).

Prohibited waste discharge

Plumbers should note that the Liquid Trade Waste Regulation Guidelines prohibit waste discharge from the following devices to any council sewerage system (see page 171):

  • Food waste disposal units – the connection of food waste disposal units (also known as in-sinkerators, in-sink food waste disposers, or garbage grinders) in non-residential premises to a council's sewerage system is not permitted. Existing installations in hospitals and nursing homes may be permitted to remain connected, provided the wastewater is pre-treated by an adequately sized grease arrestor.
  • Devices that macerate or pulverise waste – macerators and any other similar devices that are used for pulverising solid waste must not be connected by trade waste dischargers to a council's sewerage system. Solid waste includes, but is not limited to, animal waste, sanitary napkins, placenta, surgical waste and disposable nappies, bedpans and urine containers.