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Find out about the requirements for discharge of water from commercial swimming pools and spas to the wastewater system.

Classification and acceptance

Backwash and drainage from domestic swimming pools and spas are not considered as trade waste and are not permitted to be discharged to sewer. For disposal options, please contact your local council. Backwash and drainage from “Aquatic Facilities” as defined in Health (Aquatic Facilities) Regulations 2007 (WA) must apply for a Trade Waste Permit prior to connection to sewer and meet all applicable Trade Waste policies.


  • Wastewater discharges from sand bed filters do not require settleable solids arrestor.
  • Wastewater discharges from other mediums, including diatomaceous earth filters, must discharge to a settleable solids arrestor prior to discharge to sewer. This is required to ensure that any diatomaceous earth is removed and does not cause blockages in the sewer network.
  • The rate of discharge not to exceed the Water Corporation's current limits. An appropriately sized backwash tank is usually necessary.
  • The level of chlorine is not to exceed the Water Corporation's current limit of 10 milligrams per litre (as residual chlorine).
  • Trade Waste Quality Quantity usage charges and installation of Trade Waste Monitoring Point (as per Typical Drawing HX33-20-00) may apply. This requirement will be assessed as part of the Trade Waste Permit approval process.
  • In regional areas, it may not be possible to accept aquatic facilities discharge to sewer due to its salt loading on the wastewater treatment system. This will be assessed as part of the Trade Waste Permit approval process.
  • Discharges other than filter backwash, such as pool drainage for maintenance, need prior approval. You must notify us at least 7 days prior to the proposed discharge.