Greywater is waste water from the bath, shower, hand basin and laundry which can be diverted for reuse on lawns and gardens. Kitchen greywater is not suitable for reuse, as grease and oil can clog irrigation systems and build up on soil surfaces.
Under the state government's Plumbing and Drainage Act 2018, residents in sewered areas may use greywater by means of:
- manual bucketing
- connecting a flexible hose to a washing machine outlet
- installing greywater diversion devices (with council approval) and treatment plants by licenced plumbers, connected to an irrigation hose
- surface or sub-surface system (with council approval).
Care should be taken if reusing greywater because of its:
- potential health risks to humans
- potential for environmental damage to soils, ground water, and waterways caused by increased nutrient and chemical levels.
Approval for greywater diversion and treatment systems
You will need a council permit before installing either:
- a greywater diversion device, which diverts greywater from the bath, shower, hand basin and/or laundry to an irrigation hose. Untreated greywater cannot be stored
- a greywater treatment system, which collects the greywater and treats it to a high standard for reuse as garden irrigation.
You don't need a permit for manual bucketing or connection of a flexible hose to a washing machine outlet.
Information for plumbers
The greywater guidelines for plumbers on the Department of Housing and Public Works website can help plumbers assess whether the home owner has suitable and sufficient land to distribute greywater.
Plumbers should use the guidelines to give advice on the purchase and installation costs of greywater systems, prior to the home owner making an application to council.