Greywater is recycled water from domestic use in the home. It includes water from baths, showers, hand basins and washing machines (preferably the final-rinse water).
Greywater from the kitchen (including dishwashers) should not be used because the concentration of food wastes and chemicals are not readily broken down by soil organisms.
Using greywater can keep your garden thriving during periods of low rainfall; however, you need to know how this affects your home, garden and environment.
If used incorrectly, greywater can damage your soil, plants or even put your family and pets at risk. This is because greywater has chemicals and bacteria in it, which in the wrong place can cause problems.
You do not need permission to divert greywater from the shower and washing machine for immediate use on the garden.
However, if you are interested in a permanent greywater treatment and reuse system, you need an EPA-approved system and a permit from your local council.
Visit the Enviornmental Protection Authority (EPA) website or contact your local council for more information.
Setting up a greywater system
Use the safest source of greywater wherever possible.
The safest greywater is from the rinse cycle in your washing machine. The wash cycle is the next safest, followed by bath or shower water.
It's a good idea to stop using greywater if somebody in the household is sick with a stomach bug, measles or the flu, as this can increase the risk of other people becoming ill.
Divert water directly to the garden. This means whenever you shower or wash clothes, your garden is watered.
Don't store greywater for more than 24 hours. While it might be tempting to store the greywater in a drum or tub to use later, this is risky because bacteria in greywater can multiply rapidly.
Children and pets
Keep greywater safely out of reach of children, dogs and people by using it only on the roots of plants.
The best irrigation systems are piped underground (often using Agri Pipe or similar), although some people also use drip irrigation or put piping under mulch.
Avoid spraying or hosing with greywater. This just spreads the chemicals and bacteria around and can burn your plants.
Keeping food healthy
Food that is eaten raw should not be watered with greywater. Cooking helps protect against harmful bacteria that may end up on the surface of the plants.
Gardeners who cultivate native plants need to choose laundry detergents very carefully. Make sure you buy low-phosphorous detergents, as some native plants are extremely sensitive to high phosphorus levels.
Using quality water
All plants will need laundry detergents with low salt levels. (Liquid detergents generally have less salt.)
Too much salt is bad for you and your garden so:
- choose garden-friendly, biodegradable detergents and cleaners low in salt and phosphorous. Check the labels before buying these products.
- turn your greywater diverter off when cleaning, bleaching or washing heavily soiled items like dirty nappies.
- set up your irrigation system to cover as large an area as possible. The larger the area you can spread the water over, the better it dilutes any nutrients and salts in the water.
Protect local creeks and environment
Greywater must not run off your property to the street or your neighbours' property. Your neighbours have the right to lodge a complaint with your local council if it does.
Allow a strip of land between your irrigation system and the edge of your property.
Make sure irrigation is underground, drip, or under mulch to keep it safely away from people and pets.
Greywater systems may require a council permit. Please check with your local council for its requirements.