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 there 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.
For further information on guidelines and requirements for installing and operating a greywater diversion device and/or treatment system refer to NSW Guidelines for Greywater Reuse in Sewered, Single Household Residential Premises PDF.
