Installing greywater systems

Greywater is waste water generated from baths, showers, washbasins and laundries. This water can be diverted for use on lawns and gardens.

Using greywater

To divert greywater from laundries and bathrooms, you can:

• use a bucket to manually remove untreated greywater (except kitchen greywater)
• connect a flexible hose to a washing machine outlet
• as a licenced plumber, install a greywater diversion device or greywater treatment plant (with local government approval).

Kitchen greywater is not suitable for use in sewered areas. Grease and oil from the kitchen sink can clog the plumbing. In unsewered areas, put kitchen water through a grease trap first.

Storing untreated greywater

Don't store untreated greywater. After 24 hours, stored untreated greywater stored may:

• turn septic
• give off offensive odours
• provide conditions for the growth of micro-organisms
• breed mosquitoes.

Make sure there's an option to divert greywater to the sewerage system, in case it's not practical to use greywater immediately (e.g. during wet weather).

Using untreated greywater safely

Use greywater with care. Greywater must not cause a danger, health hazard or nuisance through ponding or by creating run-off on to neighbouring properties, causing an odour. To help prevent this, we prefer 'below ground' irrigation systems, as they can be designed to suit the soil and other conditions in a garden.

When establishing a greywater system:

• make sure it can't enter swimming pools or flow into neighbouring properties
• avoid ponding, bad smells or damage to plants by restricting use or moving the outlet
• keep it away from children's play areas.

Greywater diversion devices

A greywater diversion device can divert greywater to an irrigation system. They can include a filter that screens out hair, lint and other solids.

The device must:

• be fitted with a switch to divert greywater through to a subsurface or surface irrigation system
• automatically divert to the sewer if there is a blockage
• have WaterMark approval and comply with plumbing laws
• be installed by a licenced plumber.

You can control irrigation with the volume and type of greywater diverted.

Check approval requirements with the local council before installing a greywater diversion device.

Commercial applications for greywater

Since January 2008, building class and volume restrictions on commercial premises no longer apply. Commercial buildings can re-use greywater.

Regulations for supplementary water sources

The Queensland Development Code for supplementary water sources applies to all class 3 to 9 buildings, and any associated or ancillary class 10 buildings, that are required to have alternative water sources. Read more about building class types.

Check with your local council to see if the code applies to new commercial buildings in your area.

You can meet the requirements for alternative water sources through a range of options, including the use of treated greywater.

Read section MP 4.3 Supplementary water sources – commercial buildings in the Queensland Development Code for more information.

Greywater treatment plants

A greywater treatment plant collects, stores, treats and disinfects greywater to specific standards. They can be installed in sewered and unsewered areas. Refer to the Queensland plumbing and wastewater code (PDF 1.1MB) to see the level of treatment required for particular end uses.

Potential end uses include:

• flushing toilets
• providing water to the laundry (e.g. cold water source to washing machines)
• washing vehicles
• washing down paths and walls
• irrigating lawns and gardens.

Pre-approved systems

The Department of Housing and Public Works has already approved greywater treatment plants below:

Closed loop greywater treatment plants

Closed loop greywater treatment plants process, recycle, and reuse generated greywater, but maintain the same cleaning performance as current systems.

Before installing a closed loop treatment system, make sure it has a treatment plant approval in accordance with the Queensland plumbing and waste water code (PDF, 1.1MB).

Local procedures

Make sure you're familiar with local council procedures for installing greywater devices, including:

• how to lodge applications
• what forms and fees are required.

Also consider…

• Read more about the management and use of water in Queensland.
• Learn about saving water in your business.