Trade Waste

It’s the Business owner’s responsibility to make sure all Trade Waste devices are maintained accordingly and to notify Water Services via email once the service has been completed and supply a copy of the Receipt/Service Docket to:

What is Trade Waste?

Trade waste is the liquid waste from any industry, business, trade or manufacturing premises, other than domestic sewage from a hand basin, shower, bath, toilet or other domestic fixture. If you're disposing waste to the wastewater system, you need to ensure you have a Trade Waste Permit because uncontrolled or illegal discharge of Trade Waste causes serious problems in the sewer system including flooding and overloading, blockages, corrosion, hazardous work environments, even failure of sewage treatment processes. The City is responsible for preventing these contaminants from entering the sewerage system, ensuring that the health and safety of the community and the environment are protected.

Failure to maintain a Trade Waste device causes multiple different issues to both the Business Owner/Property and the City’s Sewer System such as flooding inside stores and downstream of a device which goes into the street or affects residents’ homes. Overloading, blockages, corrosion, hazardous work environments and even major failure of sewage purification processes at the Wastewater Treatment Plant are caused by failure to maintain Trade Waste devices.

What Waste Category am I?

There are 3 categories of Trade Waste:

Class I:
Class I Trade Waste consists of the following business types that discharge wastewater to the City's sewer scheme:

  • Hospitals
  • Medical Centres
  • Radiology Clinics
  • Vets
  • Boarding/Lodging houses
  • Commercial swimming pools

Class II:
Class II Trade Waste consists of the following business types that discharge wastewater to the City's sewer scheme:

  • Take away shops
  • Restaurants
  • Butchers
  • Bakeries
  • Laboratories
  • Schools (Science Lab and Kitchen)

Class III:
Class III Trade Waste consists of the following business types that discharge wastewater to the City's sewer scheme:

  • Mechanical Workshops
  • Fuel Stations
  • Car Washes/Wash Down Bays
  • Laundromats

Servicing your Trade Waste Device

Pump out frequencies are determined by the Class of Trade Waste, type of discharge, amount of customers/foot traffic and the size and working volume of each device.
Your responsibilities are to:

  • Have your Trade Waste device pumped when required - Note: each device is different and you should consult the manufacturer in regards to frequency
  • Use a licensed liquid waste contractor
  • Report pump outs and provide a Service Docket to us within 7 days -
  • Maintain good housekeeping practices

For further information see below.
If you are unsure if your business produces Trade Waste, please contact the City on 9021 9600 for further assistance.

Class I

Medical wastes consist of pharmaceuticals, antibiotics, microbes and pathogens, excreta and other fluids secreted by patients, blood and other biological and anatomical products from surgery, shower water, laundry releases, and disposable solids. All of these discharges pose a potential risk detrimental to the Wastewater Treatment Plant’s operations.

Swimming pool water contains a range of treatment products such as chlorine, salt, acid, and filtration media (sand, diatomaceous earth). In addition, the water contains dirt particles (sediments), wind-blown materials such as leaves and lawn cuttings, as well as body oils, sunscreen residues and potentially harmful bacteria. In areas connected to the sewerage system, backwash water from all swimming pools can be directed to a sewerage drainage point. New swimming pools should be permanently connected to the sewer at the time of installation or construction.

Class I Trade Waste Devices:

  • Dry basket arrestor
  • Bottle Trap Separator
  • Plaster Arrestor
  • Silver Recovery Unit
  • Sand Filters - Commercial swimming pools
  • Settleable Solids Arrestor

All Class 1 devices require cleaning based off the Manufacturers Recommendations. (Stated on Trade Waste permit).

Class II

The Grease and Fat contained in wastewater can accumulate both in your drains and the City's sewer system, resulting in blockages and overflows. The potential cost to your business associated with a drain or wastewater blockage can be significant, not only in finding and clearing the blockage but also the effect it has on the normal operation of your business. You should be aware that if a wastewater blockage is attributable to your business you may be required to pay the substantial cost for removing the blockage and the associated clean up.

Laboratories do not usually discharge large volumes of liquid waste but often dispose of a range of chemicals such as acids, alkalis, dissolved salts, nutrients and organic solvents. These wastes may produce adverse localised effects in the sewer scheme, disrupt biological Wastewater treatment processes and contaminate drain systems.

Class II Trade Waste Devices:

  • Grease Arrestor
  • Dilution Pit

Dilution Pits require cleaning based off the Manufacturers recommendations. (Stated on Trade Waste permit).

Grease Traps require cleaning when:

  • The frequency time frame is near
  • The total amount of Fats, Oils and Grease (FOG) exceeds 30% of the effective depth of the Grease Trap
  • There are gross solids or oil and grease visible in the Trade Waste sample point or downstream of the Grease Trap

Grease Traps – How can you minimise problems and reduce service costs:

  • Don’t pour grease or fats down the sink, including batter mix or food scarps. Put these in the garbage;
  • Recycle all spent cooking oils. Most used cooking oils are suitable for recycling. Check the Yellow pages for recycling companies and;
  • Don’t overuse detergent and ensure it is biodegradable.

Class III

The wastewater from mechanical workshops can contain contaminants such as fuels, solvents, heavy metals, battery acids, flammable substances, caustic cleaners, coolants, paints, fillers, grit and residue. If not properly managed, these substances make their way to the Wastewater Treatment Plant which impacts on the Treatment process and effects the quality of recycled water.

Silt from Laundromats can interfere with the sewage system’s ability to flow without obstruction. As Silt builds up, the risk that water will not drain away increases, causing flooding on the surface, and ultimately overflowing onto the surface.

Class III Trade Waste Devices

  • ​Plate/Coalescing Oil Separator
  • Triple Separator
  • Vertical Gravity Separator (VGS)
  • Silt Pit
  • Cooling Pit


Silt and Cooling Pits require cleaning based off the Manufacturers recommendations. (Stated on Trade Waste permit)

VGS and Plate/Coalescing Oil Separators require cleaning based off of:

  • The Trade Waste permit set frequency
  • A Lab sample of the effluent water outlet discharge exceeds 10mg/L

Triple Separators require cleaning based off of:

  • The Trade Waste Permit set frequency

Service Expectations

To assist the waste contractor, the area on and around the Trade Waste device is to be kept clean, tidy and free of obstructions at all times. Access must be maintained at all times for both your waste contractor and our personnel.
Covers, filters, baffles and connections are to be regularly checked for damage or deterioration and where applicable, lids must be greased at least once a year to ensure an air-tight seal is maintained between the covers and the frame.

Your Trade Waste device must be serviced by a Licensed Controlled Waste Contractor. There are some exceptions to this condition.

What you can expect from your service:

  • Remove all covers and completely empty each section of the device using a suction/vac hose
  • Scrape the internal walls of the device to remove all grime, crusts’, grease and any solids remaining (if any)
  • Hose down internal areas of the device (when a water supply is available) and use the suction/vac hose to remove remaining residue
  • Where required put fresh water back into the device
  • Securely replace all covers


An Assessment is the initial investigation that is carried out by Water Services to determine a Frequency for new businesses. Water Services review the working volume, the type and amount of discharge a Trade Waste device is processing to determine the approximate amount of time the device will reach capacity and exceed the effective working criteria (Frequency).

You must adhere to the pump-out frequency nominated for your Trade Waste Device which is stated on your Trade Waste Permit. If the volume or nature of your business evolves, then you must contact Water Services to request a reassessment. (See: ‘Reassessing your Frequency’).


An Inspection is when Water Services Officers view the current condition of a Trade Waste device. A Visual Inspection, Sludge Judge Test or Lab Sample is conducted to determine whether the device is being maintained correctly, it is still in satisfactory working order, the Frequency is being followed and that the Frequency is still correctly set for the device to reach capacity/discharge criteria.

Note: A single annual inspection from Water Services is covered in the Annual Trade Waste fee

Annual Inspection
Every Trade Waste premises will receive a minimum of one inspection per calendar year.
This inspection is to check the following:

  • The structure of the Trade Waste device is still functional and up to standard
  • That the Trade Waste device is being serviced in line with the set frequency from the City
  • That the current frequency is still accurately set for the amount of waste the business is producing
  • To offer education and advice when required
  • To ensure the service you are receiving from your contractor is meeting the correct cleaning and maintenance standards as set by the carrier company and the City of Kalgoorlie-Boulder.
  • Water Services also conduct random inspections from time to time to make sure the Frequency is correct.

Reassessing your Frequency

You may request for us to undertake a Reassessment of your Trade Waste frequency due to:

  • Change of Ownership (See Assessments)
  • Increase or decrease in volume of contaminants produced
  • Changes in the volume of service/customers
  • Upgrades or changes to the Trade Waste device
  • Change in what services are being provided on site

This could be a onetime request by a business as, for example, for some reason business has dropped off for a two week period, therefore the device will not have reached capacity.

Otherwise a series of assessments is completed to determine a new period the device exceeds the discharge criteria because it is being maintained at a higher level by the business.

Note: Frequency reassessments are free of charge as it is included in the annual trade waste fee. These can be requested at any point in time by a business if you believe your device has not reached capacity by the next service date.

Reasons the City may change your frequency:

  • Service frequency is not being followed
  • Contaminants have been detected in the sewer line close to your business and the city needs to investigate where the source has come from
  • Damage has been reported to the city in regards to your Trade Waste device

Decommissioning a Trade Waste Device

If you plan to cancel your Trade Waste Permit and/or shut down your Trade Waste device, you need to let us know before doing so. If you are not the property owner, you will need to provide written permission from the owner to disconnect the fixture. 

A licensed plumber will have to come to remove the fixture, bridge the fixture or re-route your wastewater lines to bypass the fixture.

If a fixture, such as a Grease Arrestor or dilution pit, is shut down but left in place, it must first be cleaned and pumped out by a licensed liquid waste contractor. You then must provide the final pump out docket from the contractor to Water Services by emailing a copy to

Quick Links

Water Corporation - Trade Waste Information

Water Corporation - Fats, Oils and Grease Management

Acceptance Criteria for Trade Waste

Trade Waste Application Form

Typical drawings for trade waste devices