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 discharges trade waste, you may need a trade waste consent.

The information in this section is a guide, please contact us to discuss your specific situation and check out the list of businesses often requiring a trade waste consent below.

You can contact one of our Trade Waste Officers to discuss your project at any stage by phoning 06 759 6060, completing the contact us form or emailing

Applying for a trade waste consent

We grant trade waste consents on a case-by-case basis. When considering a consent we assess 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 visit your business and may take some samples of your trade waste for analysis. For more information on the trade waste consents see the Trade Waste Bylaw

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.

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: 

Businesses that may need a trade waste consent

  • Bakeries
  • Beverage manufacturers
  • Car washes
  • Churches (with catering facilities)
  • Clothing manufacturers
  • Concrete batching plants
  • Dairy products processing
  • Dentists
  • Doctor surgeries
  • Drycleaners
  • Electroplaters
  • Footwear manufacturers
  • Foundries
  • Galvanisers
  • Hotels and motels (with catering facilities).
  • Hospitals.
  • Landfills (leachate discharge).
  • Laundries.
  • 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
  • Marae
  • Meat, fish and shellfish processing facilities
  • Mechanical workshops/service stations
  • Metal surfacers
  • Mortuaries
  • Photo and medical laboratories
  • Photo processors
  • Premises with commercial waste masters
  • Printers
  • Restaurants
  • Retail butchers and fishmongers
  • Schools, polytechnics, universities
  • Scientific laboratories
  • Spray painting facilities
  • Stock sale yards
  • Take away premises
  • Tanneries and leather finishers
  • Textile fibre and textile processors
  • Truck wash facilities
  • Veterinary surgeries
  • 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!
    • 11.26 % of the wastewater volume treated at the Wastewater Treatment Plant comes from 61 businesses.
    • 19.88% of the wastewater organic load treated at the Wastewater Treatment Plant comes from the same 61 businesses.
    • 1600 tonnes of biosolids (the by-product after wastewater is treated) are produced each year.
    • There are 107 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 450mg 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 230mg of oxygen for every litre of wastewater treated.
    • 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.