Tuesday, 9 September 2008
| 11ºC – Fair
| Telephone: 02 9777 1000
A household’s greywater is any water that comes from use by non-toilet plumbing fixtures or the kitchen sink. Kitchen wastewater is generally heavily polluted with food particles, oils, fats, and other waste and is often more polluted than blackwater or raw sewage.
This means that showers, hand basins and washing machines produce greywater. By reusing greywater up to 400 litres of freshwater per average household could be saved every day.
Uses of greywater include watering plants and flushing the toilet. It can even be used for washing clothes if properly treated. You can reduce your water bill, help the environment by using less water, and save money on the cost of new or upgraded sewerage infrastructure.
However, there are some problems with using greywater which must be carefully considered before it is attempted. There is the cost of installing and maintaining the system which must be individually designed for each household’s water usage patterns. There is also the potential for health risks and environmental pollution due to the impurities and micro-organisms that enter the water as it is used the first time.
Some potential negative environmental impacts from greywater reuse are:
- Contaminants from cleaning products building up in soil
- Some detergents increase the pH level of soil and should not be used
- Bleaches and disinfectants can kill beneficial soil organisms
- Fats and oils can repel water if they build up in the soil
- Overwatering will mean greywater ends up in stormwater drains which flow into the river and harbour
- Soil around buildings can be saturated with salt and become permanently boggy
- Permanently saturated soils stop plants from growing and smells.
Greywater usage may not be suitable for all sites and homes. While it can save a lot of water, due to the costs and problem associated, other conservation methods should be adopted first. Council will consider greywater reuse schemes on their likelihood of succeeding.
Requirements for approval for installation and use:
- Council cannot approve a greywater system for use unless it has been accredited by the NSW Department of Health
- Approval for installation and operation must be granted by Willoughby before the system can proceed. Regular inspections and soil analysis will be required. A soil analysis of the site and a permeability study must be carried out by a qualified person
- Plumbing must comply with Sydney Water guidelines to prevent backflow into drinking water and to provide a diversion into the sewer if the system fails
- No reuse system within 50 metres of a water course will be approved
- If earthworks are required to install, a development application and consent under the Environmental Planning and Assessment Act is needed; Council will waive normal fees.
Important websites to visit are NSW Health and Sydney Water.