Approved greywater systems

Greywater is the wastewater from:

• showers
• baths
• hand basins
• washing machines
• dishwashers
• sinks in kitchens and laundry sinks.

It does not include toilet waste.

The Code of Practice for the Reuse of Greywater in Western Australia 2010 (PDF 1.3MB) provides information on the requirements for the reuse of greywater in household gardens.

The Code provides guidelines for:

• householders
• persons wishing to design and market systems.

There are 2 types of greywater reuse systems used in WA:

• greywater diversion device
• greywater treatment system.

Greywater diversion device

The greywater diversion device (GDD):

• diverts greywater without storage or treatment
• incorporates a hand activated switch or tap to divert the greywater to the garden or the sewer.

Greywater from a GDD must only be reused in gardens via sub-surface irrigation only.

All Greywater Diversion Devices (GDD) products must be WaterMark certified to ensure they are fit for purpose and authorised for use in plumbing and drainage installations.

To check currency of the GDD certified products  go to the WaterMark Certification Scheme Product Database.

There are 2 types of GDDs:

Gravity GDD

A gravity GDD incorporates a hand activated valve, switch or tap. It is fitted to the outlet of the waste pipe of the plumbing fixture, such as a laundry tub.

GDD are not permitted to be fed with greywater from the kitchen. Greywater from a gravity GDD is diverted directly to a subsurface irrigation system in the garden.

Pump GDD

A pump GDD incorporates a surge tank to cope with sudden influxes of greywater.

It is used for the distribution of greywater directly to a subsurface irrigation system in the garden.

The surge tank does not operate as a storage tank.

Greywater disposal system

The subsurface irrigation system connected to the GDD must meet the requirement of   Code of Practice for the Reuse of Greywater in Western Australia 2010 (PDF 1.3MB), disposal area should size according to the Health (Treatment of Sewage and Disposal of Effluent and Liquid Waste) Regulations 1974 (external site).

Greywater treatment system

A greywater treatment system (GTS) collects and treats greywater to a higher quality.

Treated greywater that is not disinfected may only be reused via subsurface irrigation.

Disinfected greywater from a GTS that achieves water quality targets may be used for:

• surface irrigation
• toilet flushing
• cold water supply to washing machine.

It should be noted that conditions of approval may vary, depending on the design. Some GTSs:

• are not permitted in unsewered areas
• do not accept kitchen waste.
• are not available on a smaller scale.

Developers interested in large wastewater reuse schemes or in-house reuse for commercial or subdivision developments should refer to the Australian Guidelines for Water Recycling: Managing Health and Environmental Risks (Phase 1) 2006 (external site).

Environmental Health Directorate
Department of Health
Phone: 9222 2000
Email: ehinfo@health.wa.gov.au