Greywater

Greywater is household wastewater that has not come into contact with toilet waste. It comes from the kitchen sink, dishwasher, bath, shower, bathroom hand wash basin, clothes washing machine, and laundry trough.

Long term sustainable greywater reuse should be in accordance with the greywater reuse policy and as required under current legislation.

This is because greywater can contain disease-causing organisms, detergents, soaps, nutrients, oils, salts and particles of hair, food, lint, etc. Unless properly managed, these characteristics can give rise to health risks and degradation of the environment.

Kitchen wastewater is generally not recommended for reuse as it can be heavily polluted with contaminants which are very alkaline and may be harmful to soils and plants by altering their characteristics in the longer term.

Untreated greywater is generally suitable for subsurface use provided that storage times and capacities are designed to minimise generation of odours. For drip irrigation, a treatment process similar to secondary treatment for sewage will normally be required. Where higher exposures are possible, more extensive treatment will be required to meet the water quality targets required for treated sewage.

The following measures will help to reduce the public health and environmental risks associated with the use of greywater:

  • Do not use sprinklers to distribute greywater.
  • Only subsurface irrigation systems can be used.
  • Ensure that any subsurface system that is installed goes through the correct approval process by council.
  • Do not put greywater on food plants.
  • Do not place greywater on lawns where children are likely to play.
  • Do not allow greywater to leave your property and enter your neighbours property or the stormwater system.
  • Ensure that the greywater does not create a nuisance, for example through odours or ponding, by storing untreated greywater for a maximum of 24 hours.

Approval

An application will need to be submitted to Council when installing a grey water system. An approval for an activity under Section 68 of the Local Government Act 1993 can be sought from Council under two separate assessment processes. These two processes are either as a standalone application for the activity, or in conjunction with a Development Application which is seeking approval under the Environmental Planning and Assessment Act 1979 for a use to which the activity is related

Section 68 of the Local Government Act 1993 contains a list of activities that require approval from Council. If s68 activities are to be undertaken independently from a development application (DA), a completed application for s68 approval needs to be submitted.

If the s68 works are to be carried out as part of a DA, a separate s68 application form is not required, if the appropriate box(es) are marked on the DA form.

Mosman Council Greywater Policy

For further information see Water Conservation – Greywater.

NSW Office of Water - Greywater

Greywater Recycling Basics

Urban Greywater Design and Installation Handbook