Greywater is water that is discharged from household appliances (such as washing machines and dishwashers) and from sinks, showers and bathtubs. It does not include water discharged from toilets - this is called “black water”.

Reusing greywater can conserve water and save you money.

But be aware - greywater contains microorganisms and can be harmful to your health and to your garden. Certain approvals must be granted before you establish a greywater recycling system on your property and there are strict regulations for its use.

Approval is required from three agencies to ensure that systems operate and maintain a standard which will protect users and the environment:

• SA Health approves the treatment process and use of reclaimed greywater. Information regarding greywater systems, regulations and approval processes is available from the SA Health website.
• Local government approves the planning and development aspect of proposed systems. If you want to install a greywater system in a sewered area or in an area with a Septic Tank Effluent Drainage scheme (STED) you need to contact the Department of Health and Ageing and obtain approval for diverting greywater from the sewer or the STED scheme system.
• If changes to your plumbing are required, approval from the Office of the Technical Regulator (OTR) must also be obtained prior to installation of the approved SA Health greywater system. The OTR approves changes to plumbing and drainage through an encumbrance mechanism to protect its sewer system and to be able to ensure that if the property changes ownership, there is a mechanism to contact the new owner of the modified plumbing arrangements. Any queries, please call OTR on 1300 760 311.

Ways to use greywater

Generally most people choose to use greywater to water their garden. Kitchen greywater should not be included in this type of reuse option as it contains a higher number of harmful micro-organisms as well as particles that may cause blockages in irrigation systems. In the garden, greywater should never be used to water plants that might be consumed raw.

Greywater for toilet flushing requires a higher level of treatment than for garden irrigation. When you flush the toilet you create an aerosol-like effect, so greywater must be treated to a certain standard to protect your health. In addition, some problems have been experienced with toilet cisterns operating on greywater due to microbial growth interfering with the flushing operation.