Greywater is wastewater from baths, showers, hand basins, laundry tubs and washing machines. Greywater may contain fats and oils, soap, shampoo, toothpaste, laundry detergents, hair and lint. If stored, the water breeds bacteria and turns grey. Untreated greywater cannot be stored for longer than 24 hours.
Untreated greywater can be used carefully on gardens and lawns.
You can choose to install a system to treat your greywater to make it suitable for other uses around your home.
Using untreated greywater
It is easy to collect water from your shower and washing machine by bucket. You can empty the water onto your gardens or lawn. You do not need approval from Brisbane City Council.
Hose connected to your washing machine
You can connect a greywater hose to your washing machine water outlet. Place the other end of the hose outside to pump water onto your lawn and garden. Ensure the hose is within your property and your garden requires watering to ensure there is no run-off. You do not need approval from Council.
Always set up the hose so it runs downhill. This will ensure the washing machine can easily pump the water out. Check the washing machine manufacturer’s guidelines to ensure you don’t void the warranty by placing a greywater hose on the water outlet.
Greywater diversion device
For a more permanent system, you can hire a plumber to install a greywater diversion device. The greywater from your laundry and bathroom flows through a filter to remove solids. You can store this water for a few hours then use it to irrigate your garden. Manual and automatic diversion devices are available. It is important to ensure that over-watering does not lead to run-off or ponding. This can cause a health issue for you or your neighbours. You can estimate how much greywater your home or business produces and needs.
Not all devices available meet Australian standards. Look for products carrying a watermark product certification. You can only install approved devices in Queensland.
Council requires sub-surface irrigation systems when using untreated greywater on your garden.
A licensed plumber will need to install your diversion system.
Some homeowners and businesses may choose to install a reuse facility to make even greater use of greywater on their property. You can use treated greywater for:
- lawn and garden irrigation
- toilet flushing
- washing of paths, walls and vehicles
- laundry and washing machine use (cold water source only).
Greywater treatment systems collect, clean, store and disinfect greywater. They treat organic pollutants in the greywater. Most do not remove chemicals such as sodium, nitrate or phosphorus. Disinfection methods can include chlorination, ultra-violet radiation or ozonation to remove pathogens. Greywater must be treated to the standards specified in the Queensland Plumbing and Wastewater Code prior to use.
The quality of the treated greywater will determine its use.
Only systems with watermark approval may be installed in Queensland by a licensed plumber.
For further information about greywater reuse facilities and statutory requirements refer to the Business Queensland website.