About Liquid Trade Waste

The Local Government (General) Regulation, 2005 defines “trade waste” as all liquid waste other than sewage of a domestic nature.

Commercial Kitchen

What is Liquid Trade Waste?

Section 3 of the Local Government (General) Regulation, 2005 contains the following definition:

“sewage of a domestic nature includes human faecal matter, urine and wastewater associated with ordinary kitchen, laundry and ablution activities of a household, but does not include waste in or from a sewage management facility.”

To explicitly differentiate trade waste as defined above from the other wastes also generated by industry and commerce the term liquid trade waste is now generally used by regulatory authorities. For the purposes of this application the term “liquid trade waste” is considered to have the same definition as “trade waste”.

NB. While stormwater and unpolluted water are not considered as liquid trade waste they are still not allowed to be discharged to Council sewer without approval.

Shoalhaven Water regulates liquid trade waste discharges in order to:

  • Protect the health and safety of our staff, the public, and the environment
  • Protect wastewater system infrastructure, assets, and sewerage treatment processes to protect the effluent and biosolid quality for facilitation of recycling
  • Reduce maintenance costs and odour complaints

This includes liquid waste from: 

  • Industrial premises
  • Businesses and commercial premises such as - beauticians, florists, hairdressers, hotels, motels, restaurants, takeaway stores, butchers, service stations, mechanical workshops, vehicle wash facilities, supermarkets, dentists
  • Community and public premises such as - craft clubs, pools, schools, colleges, education facilities, hospitals and nursing homes
  • Any of the above activities carried out at residential premises
  • Septic tank waste, waste from marine pump-out facilities and established sites for the discharge of chemical toilet or pan contents from mobile homes, caravans or portaloos to the sewerage system

If your business falls into one of these categories, you will be required to pre-treat your liquid trade waste prior to discharging into our sewerage system.

What is Pre-treatment?

Pre-treatment is achieved by using a device or piece of equipment to treat the liquid trade waste prior to discharging into the sewerage system. The type of pre-treatment device required is dependent on the nature of the activity and the volume and strength of the liquid trade waste it generates.

Typical pre-treatment devices used for the treatment of liquid trade waste include but are not necessarily limited to the following:

  • Grease arrestor (grease trap)
  • Basket arrestor with fixed screens (dry basket arrestor)
  • Fixed or removable screens
  • Coalescing plate interceptor (CPI oil separator)
  • Vertical gravity separator (VGS separator)
  • Hydrocyclone separation system (HSS separator)
  • Cooling pit
  • Balancing, averaging, neutralising pit/tank
  • Solids settlement pit / silt arrestor
  • Plaster arrestor

Shoalhaven Water’s pre-treatment requirements are in accordance with the Liquid Trade Waste Regulation Guidelines, 2009 and Liquid Trade Waste Policy.


A common question we encounter from our local hospitality industry is "I operate a food business, do I need a grease arrestor?"

The answer is usually yes! Most food businesses will need to have a 1000L capacity grease arrestor (grease trap) or larger installed to pre-treat the liquid trade waste prior to discharge to the sewer.  The size is determined by a number of factors, such as available seating or kitchen fixture units, and is individually assessed according to the NSW Liquid Trade Waste Regulation Guidelines in force at the time.

Council’s Liquid Trade Waste Discharge to the Sewerage System policy outlines the type of food businesses that require, and those that may not require, the installation of a grease arrestor.

If you are considering starting up or purchasing a food business, it is important to understand the type of cooking, preparation and serving you will be doing, to determine if a grease arrestor is required. 

If a grease arrestor is already installed on the premise, you need to consider if it is the correct size and in good condition. If there is none at the property, you will need to contact a licensed plumber for advice and a quote.  They can also check if there are any installation issues (eg due to lack of space).


What are my requirements if I operate a mechanical workshop?

Liquid trade wastes that are discharged from mechanical workshops and vehicle wash businesses are required to be pre-treated using an oily water separator and associated collection pits and pumps. Separators, pits and pumps need to be sized properly for the activity and amount of waste generated.  Minimum size for oily water separators is 1000L/hr.

Double and triple interceptor pits and general-purpose pits are no longer appropriate pre-treatment equipment on their own.  If liquid trade waste is to be discharged to sewer, the pre-treatment system will need to be upgraded to include an oily water separator.

An alternative is to operate as a dry workshop. This is only appropriate where a very small amount of liquid trade waste is generated.  Any pits need to be disconnected from draining to the sewer.  Any waste liquids collected on site need to be removed by a contractor.

Liquid trade wastes collected from service station covered forecourts and other refuelling locations are not permitted to discharge to sewer and will need to find alternate methods of waste water disposal.


Shoalhaven Water’s Regulatory Unit is available to provide advice and assistance to understand the particular liquid trade waste requirements for your business.

What is a Discharger Category?

Activities that generate and discharge liquid trade waste will fall into one of the following discharger categories:

Low Risk

  • Category 1A: Nil or minimal liquid trade waste pre-treatment equipment required (eg hairdresser, florist, beautician)
  • Category 1B: Still low risk but require more sophisticated prescribed liquid trade waste pre-treatment equipment (eg vehicle wash, laundry activities)

Medium Risk

Require prescribed liquid trade waste pre-treatment equipment (eg. Grease arrestor for restaurant or cafe, oily water separator for a mechanical workshop).

  • Category 2A - The prescribed pre-treatment equipment is installed and maintained to Council’s requirements (eg correct type and size grease arrestor pumped out to Council’s set frequency)
  • Category 2B - The prescribed pre-treatment equipment is not installed or is not appropriate or is installed but not maintained to Council’s requirements.
  • Category 2S - Dischargers of pan contents, septic wastes, chemical toilet waste and ship-to-shore pump-outs into the sewerage system. Includes septic tank pump outs and septage transported and discharged directly to a sewerage treatment plant. 

High Risk

Referred to as Category 3A or 3B (depending on the complexity of the pre-treatment system) and includes:

  • Industrial dischargers
  • Large volume (greater than 20kL/d) dischargers
  • Dischargers that do not fall into Category 1 or 2 above
  • Contaminated groundwater or stormwater

Approval Requirements

To discharge Liquid Trade Waste into Council’s sewerage system you are required under Section 68 Part C4 of the Local Government Act to obtain an approval to do so.

How do I get Approval to Discharge Liquid Trade Waste to Sewer?

To obtain approval, customers must submit the relevant online application based on the business activity which may include providing information such as a site plan and/or drainage diagram. 

Application is usually made by the person or organisation responsible for the operation of the business or facility, however it can be completed by the operator or property owner.   Where the applicant is not the property owner, the property owner must provide their consent.

Upon application, the request will be reviewed, and relevant application fees issued. In most cases an inspection of the pre-treatment equipment will be undertaken prior to issuing an approval.

Approvals are advised in writing to the applicant and the property owner. 

Ongoing Fees and Charges

Liquid trade waste discharged from businesses and other non-domestic sources, such as restaurants, cafes or mechanical workshops, generate a higher load on the sewerage system than normal households. In order to prevent a significant cross-subsidy from the general public to commerce and industry, appropriate fees and charges are levied for liquid trade waste discharges. 

Liquid trade waste fees and charges are in addition to non-residential sewer usage charges.

Our fees and charges include:

Application Fee – generally includes an inspection

Annual Fee – covers administration and monitoring of the discharger

Re-Inspection Fee - applies to follow up inspections due to non-compliances

Usage Charges – this does not apply to all dischargers and is dependent on the category. Usage charges apply to all Category 2 dischargers and apply to Category 1 dischargers only where there is non-compliance. Category 3 dischargers are charged Excess Mass Charges instead of usage charges.

What is a Discharge Factor?

The Liquid trade waste discharge factor is an estimate of the ratio of the volume of liquid trade waste discharged to the sewer compared to total metered water consumption. Your Discharge Factor will be shown on your quarterly Water Account.

How are Usage Charges calculated?

Discharge volumes are determined by applying the discharge factor to the metered water consumption or measuring the volume of liquid trade waste discharged to sewer.

Usage charges are usually calculated by applying the appropriate discharger category usage rate to the discharge volume for the quarter (or period).  Your Usage Charge will be shown on your quarterly Water Account.

High risk or industrial dischargers may be required to install a meter to measure the actual liquid trade waste volume discharged to the sewer.  For these category 3 dischargers, Excess Mass Charges are calculated instead of usage charges and are invoiced separately to the water account.

Non-Compliance

Usage charges significantly increase for non-compliance.

Who is responsible for paying the ongoing fees & charges?

The Local Government Act, 1993 specifies that the landowner is responsible for the payment of liquid trade waste fees and charges associated with their property. Any re-imbursement of the landowner, by a person/company (occupier) conducting the activity at the premises, for liquid trade waste fees and charges is a matter between these two parties.

Shoalhaven City Council's Fees & Charges

For more information visit Shoalhaven City Council's Fees & Charges - Liquid Trade Waste Discharge to Sewer.

Local Government Legislation

The requirements and procedures for liquid trade waste management are outlined in the Liquid Trade Waste Policy. If your business discharges liquid waste other than domestic sewage, you must submit a Liquid Trade Waste Application to Shoalhaven Water, as required under Section 68 of the Local Government Act. This applies to both new and existing trade waste dischargers.

A discharger who fails to obtain approval or fails to comply with the conditions of their approval may be prosecuted under section 626 & 627 of the Local Government Act 1993.  The Act also specifies that liquid trade waste fees and charges are to be levied, which are dependent on liquid trade waste discharger category.

Need more help?

For further information regarding Liquid Trade Waste contact us on (02) 4429 3125. 

Appointments are necessary if you come into the office to discuss.