Trade Waste

Trade waste is any commercial liquid (which is not typical domestic waste) that is discharged into our wastewater system. If not controlled, trade waste can be harmful to our wastewater network, the treatment system, the environment, our staff and the public. If you or your business produces trade waste, you may need a trade waste consent.

The information in this section is a guide, please contact our Trade Waste Officer to discuss your specific situation. 

Discharging trade waste without a consent

If you discharge trade waste before getting a consent you are breaching our Trade Waste Bylaw. The same applies if you exceed the conditions set in your consent. 

The bylaw outlines our trade waste requirements and details the process if you fail to comply. It also includes our policy on the recovery of costs for repairs and damages. If a business continues to discharge trade waste without a consent they can be convicted of an offence against a Trade Wastes Bylaw (under the Local Government Act) and fined up to $200,000.

Applying for a trade waste consent

We grant trade waste consents on a case-by-case basis. When considering a consent we take into account the quality, volume and rate of the discharge in relation to the:

  • Health and safety of our staff and the public.
  • Extent the trade waste may react with other trade waste or domestic waste.
  • Capacity of our wastewater system.
  • Nature of the activity.

We will also make a site visit and may take some samples of your trade waste for analysis.

You may not need a trade waste consent if the discharge volume is less than 5m³ within a 24 hour period and does not contain certain contaminants. The temperature must also be contained to less than 50 degrees centigrade and the pH level must be between 6.0 and 10.0 at all times. Contact our Trade Waste Officer to discuss your specific situation. 

Non-residential grease trap requirements

A grease trap is a receptacle that captures the oil and fat so it doesn't enter the sewer system and cause blockages. It is required for all non-residential activities where cooking is undertaken with fat and oils.

The guide below will help if you are setting up a new business or upgrading existing premises:

You can contact one of our Trade Waste Officers to discuss your project at any stage - contact us on 06-759 6060 or

Types of businesses that may need a trade waste consent

  • Bakeries.
  • Car washes.
  • Churches (with catering facilities).
  • Clothing manufactures.
  • Doctor surgeries.
  • Hotels and motels (with catering facilities).
  • Laundries.
  • Marae.
  • Meat, fish and shellfish processing (excluding those with commercial macerators) facilities.
  • Mechanical workshops/service stations.
  • Photo processors (modular units only).
  • Restaurants (excluding those with commercial waste masters).
  • Retail butchers and fishmongers (excluding those with commercial waste masters).
  • Schools, polytechnics, universities (with laboratories).
  • Take away premises.
  • Truck wash facilities.
  • Veterinary surgeries.
  • Beverage manufacturers.
  • Concrete batching plants.
  • Dairy products processing.
  • Dentists.
  • Drycleaners.
  • Electroplaters.
  • Footwear manufacturers.
  • Foundries.
  • Galvanisers.
  • Hospitals.
  • Landfilsl (leachate discharge).
  • Manufacturers of chemicals, and of chemical, petroleum, coal, rubber and plastic products.
  • Manufacturers of clay, glass, plaster, masonry, asbestos, and related mineral products.
  • Manufacturers of fabricated metal products, machinery and equipment.
  • Manufacturers of fertiliser.
  • Manufacturers of paper and paper products.
  • Metal surfacers.
  • Mortuaries.
  • Photo and medical laboratories.
  • Premises with commercial waste masters.
  • Printers.
  • Scientific laboratories.
  • Spray painting facilities.
  • Stock sale yards.
  • Tanneries and leather finishers.
  • Textile fibre and textile processors.
  • Waste management processors.

Did you know

  • 1,026,268m³ of waste is produced by trade waste consented businesses each year - that’s 2811m³ each day!
  • 14.46 per cent of the wastewater treated at the Wastewater Treatment Plant comes from 51 businesses.
  • 1250 tonnes of biosolids (the by-product after wastewater is treated) are produced each year.
  • There are 77 active trade waste consented businesses in New Plymouth District (e.g. electroplaters, hospitals etc).
  • Trade waste generally has higher levels of biochemical oxygen demand (BOD) and the suspended solids present are elevated levels of toxic metals.
  • Trade waste requires 420mg of oxygen per litre of wastewater to produce a clean effluent that will have no impact in the receiving environment. This compares with domestic wastewater which only requires 280mg of oxygen for every litre of wastewater treated.
  • Trade waste customers produce 400mg of suspended solids in every litre of wastewater. Domestic wastewater produces 230mg of suspended solids in every litre of wastewater.
  • Each year the cost of treating trade waste must take into account the volume, biochemical oxygen demand, suspended solids and the amount of toxic metals produced by industry.