Safe Greywater Use

Marrickville Council strongly encourages the sustainable management of water by residents including, in some cases, the safe and environmentally responsible use of greywater. However, residents must be aware that using greywater can impact on your family's health and on the environment if not managed carefully.

Greywater can be used instead of drinking water to irrigate gardens or lawns and, if treated appropriately, it can be used in toilets and washing machines. By using greywater for irrigation alone, a household can save between 50,000 and 100,000 litres of drinking water a year.

Previously, Council approval was required for greywater diversion devices to be installed in homes. The NSW Government has changed the rules, and this is no longer required provided certain conditions are met. Greywater treatment systems still require Council approval.

What is greywater?

Greywater is the wastewater from your shower, bath, spa, hand basins, laundry tub, washing machine, dishwasher and kitchen sink. It doesn't include water from toilets, urinals or bidets. Greywater from the kitchen is not recommended for reuse due to high levels of contamination.

Health and safety

All forms of household wastewater have the potential to be infectious to human health and pollute our waterways and soils. The Department of Energy Utilities and Sustainability has investigated the risks of greywater reuse and has developed the NSW Guidelines for Greywater Reuse in Sewered, Single Household Residential Premises. It is very important that you follow these guidelines when installing and using a greywater system in order to protect the health of your family, community and the environment.

Households that wish to reuse greywater need to understand and be dedicated to the principles of sustainable wastewater management. It is not a matter of installing the system and then forgetting about it. All greywater systems are complex and require ongoing monitoring and maintenance.

Benefits of using greywater

• Reducing your potable water consumption
• Reducing the amount of sewage discharged to our water ways and oceans 
• Reducing your water bills
• Watering your garden during drought

Disadvantages of using greywater

• The potential for pollution and undesirable health and environmental effects if the greywater is not reused correctly
• Initial cost of a greywater system and plumbing requirements
• Ongoing maintenance

Ways to reuse greywater

There are three ways of reusing greywater:

• Manual bucketing – small quantities of greywater are captured in a bucket for re-use outside on gardens or lawns. No council approval required.
   
• Diversion – a greywater diversion device simply redirects greywater without storage or treatment. Flow is activated through a switch which sends greywater back to the sewer during wet weather. Water is only suitable for use outside the home on gardens or lawns using sub-surface irrigation. No council approval required if all conditions are met. The system must be installed by a plumber.
   
• Treatment – a domestic greywater treatment system collects, stores and treats greywater to a high standard. Water is potentially suitable for use in your toilet or washing machine, as well as outside on gardens or lawns. Council approval is required and the system must be installed by a plumber. Council approval is only able to be given forNSW Health accredited greywater treatment systems.

Contact Council's Water and Catchments Coordinator or phone 9335 2104 for more information.

Fact sheets

The Department of Energy Utilities and Sustainability have also published a series of easy to follow fact sheets on greywater reuse for households:

• All About Greywater Reuse
• Keeping your plants and soil healthy with greywater

Other options

Council recommends you consider all water efficiency measures and rainwater harvesting options before investigating greywater reuse. It may be that you can adequately provide for your family's water needs without the use of greywater, particularly if your property is small. In order to assess your family's current water use and how much greywater your home actually produces it is helpful to conduct a water audit.

Reusing greywater sensibly can be costly as systems must be designed, installed and maintained in a manner which protects public health and is ecologically sustainable. Such costs may be better directed, in the first instance, to items such as water conservation devices and rainwater tanks which have less environmental and public health impacts.

Greywater and Marrickville soil type

Most original soils in the Marrickville are clay based which means that water is absorbed quite slowly. As chemicals in greywater often decrease the rate of absorption it is essential that Marrickville residents who are reusing water do not apply greywater too quickly as it may run off the garden surface and enter stormwater drains.

In some parts of Marrickville, for example in low lying areas along the Cooks River, the watertable is very close to the surface and thus easily contaminated. Marrickville Council does not support the diversion of untreated greywater in these areas as it poses too great a risk to public and environmental health.

Find out more on using greywater safely

• Marrickville Council holds technical workshops designed to help you find out all that's involved in using greywater on your property. You can view the workshop presentation Ecological Design by clicking here.
   
• To learn more about greywater, visit our events page to book your place in the next workshop.
   
• Contact Council's Water and Catchments Coordinator on 9335 2104 or email envuswim@marrickville.nsw.gov.au.