Greywater

Greywater means wastewater that does not contain human excreta. Greywater includes wastewater from the laundry, bath, shower and bathroom basin, but not toilet. Kitchen basin wastewater may only be included if it is treated, because it may be heavily polluted with food particles, oils and fats.

BASIX recognises the following types of greywater system:

  • Greywater diversion - water re-used for subsurface garden irrigation
  • Greywater treatment - treated water re-used for garden irrigation, clothes washing and toilet flushing depending on the level of treatment

All forms of greywater are capable of transmitting disease, and can have a negative impact on your garden if not installed and managed correctly.

Additional guidance on greywater reuse in single dwellings is available from the NSW Office of Water and the NSW Health Department.

Greywater diversion systems

A greywater diversion system is a system that diverts household greywater for re-use. It does not treat or store the water.

You will need to nominate the sources of water that will be collected for diversion. Diverted greywater can only be used for sub-surface garden irrigation.

Greywater diversion systems should not be used in areas identified as having major limitations to on-site disposal. Such areas include locations with shallow water tables, highly porous soils (such as sand beds) or with visible signs of surface dampness (such as seeps, soaks or springs). Some other limitations that must be assessed before adopting greywater diversion include soil characteristics, salinity and other contaminant loads of wastewater, scheduling application and maintaining sewer connections to provide an alternative disposal option in the case of on site system failure.

The installation of a greywater diversion system does not require approval by your local council if it is installed in accordance with the Plumbing and Drainage Code of Practice. The Plumbing and Drainage Code of Practice can be found on the NSW Office of Water website.

Greywater treatment systems

A greywater treatment system is a system that collects, treats and stores household greywater for re-use.

You will need to nominate the sources of water that will be collected for treatment. "All other household" refers to water collected from the kitchen sink. Treated greywater can be used for irrigation, toilet flushing and laundry (clothes washing).

Greywater treatment systems should not be used in areas identified as having major limitations to on-site disposal. Such areas include locations with shallow water tables, highly porous soils (such as sand beds) or with visible signs of surface dampness (such as seeps, soaks or springs). Some other limitations that must be assessed before adopting greywater treatment and reuse outdoors include soil characteristics, salinity and other contaminant loads of the greywater, scheduling application and maintaining sewer connections to provide an alternative disposal option in the case of system failure.

How do I get approval for my Greywater treatment system? 

You need to obtain approval from local council to operate a single household greywater treatment system. Your local council determines the final conditions of the approval to operate the greywater treatment system, including installation, maintenance and monitoring requirements.

Local councils can only approve a greywater treatment system that has been accredited by NSW Health. A current list of NSW accredited systems can be found on the department's website.

Did you know? New BASIX homes are predicted to have saved around 24.8 billion litres of water (or over 9000 Olympic swimming pools)

source: BASIX Five Year Outcomes Summary