Greywater can be a valuable source of water to use in the garden, particularly during dry conditions. Learn how and where to use grey water at your place.
Greywater is water that comes from household washing machines, hand basins, showers and baths. Water from dishwashers and kitchen sinks is often referred to as ‘dark greywater’ as it has a higher load of chemicals, fats and other organic matter. Dark greywater is not recommended for using on gardens. Greywater does not include water from toilets, which is referred to as ‘black water’.
When used correctly, greywater has the potential to irrigate lawns and gardens. This helps keep gardens thriving and makes the most of precious water resources, particularly during times of drought and water restrictions. Using greywater also helps to reduce water bills and the amount of wastewater entering sewers or on-site treatment systems. Consult your local council or water authority for the latest regulations regarding greywater usage in your area. In some areas, untreated greywater can only be used in sub-surface irrigation systems.
However, here is some general information on using greywater in your garden.
According to the SmartApprovedWaterMark, 15-20% of water used in homes is in the laundry (https://www.smartwatermark.org/smartwateradvice/saving-water-home/laundry/) . Large top loading washing machines can use up to 170 litres of water per cycle, which is a significant amount of water that can be directed out into the garden. Laundry greywater can be diverted from the washing machine using an appropriate greywater pipe or hose and collected in buckets or tubs.
Greywater can be collected in the bathroom by standing in a large tub while you take a shower, the water scooped out of the bath or washing your hands over a bucket in the bathroom basin.
You can make the most of greywater for the garden and turn it into plant food, by mixing specially developed Yates Greywater Fertiliser into the greywater. Yates Greywater Fertiliser has a wide range of benefits:
Mix 20 – 40mL of Yates Greywater Fertiliser into 10 L of greywater and apply around the root zone of non-edible garden plants or over the lawn every 2 – 4 weeks.
Greywater can be used to irrigate the lawn and ornamental (non-edible) garden beds. Greywater should not be used to water herbs, vegetables or other edible produce. Unless you only use soaps and detergents that contain negligible phosphorus (indicated by an ‘NP’ logo on the pack), avoid using greywater around phosphorus sensitive Australian native plants.
Potted plants should also not be watered with greywater, due to the potential build-up of salts.
Grey water can be collected in buckets or tubs (kept away from babies and children) or diverted straight from the washing machine using an appropriate grey water pipe or hose. According to the SmartApprovedWaterMark, 15-20% of water used in homes is in the laundry (https://www.smartwatermark.org/smartwateradvice/saving-water-home/laundry/) . Large top loading washing machines can use up to 170 litres of water per cycle, which is a significant amount of water that can be directed out into the garden.
It’s best to regularly move grey water hoses around the garden and lawn so the same plants / areas are not being constantly watered with grey water. A handy way to remember is to move grey water hoses from one spot to another every weekend.
It’s important to choose laundry detergents that are suitable for using in greywater. Detergents can contain phosphorus and salts that can harm some plants and affect the quality of the soil or increase the soil’s pH (make the soil more alkaline). Soil with an alkaline pH (pH greater than 7) can lead to nutrients becoming unavailable to plants, particularly iron. You may start to see plant leaves becoming pale with dark green veins, which indicates an iron deficiency. High concentrations of salts can also damage plants and lead to burnt leaves and poor plant health. If plants irrigated with greywater start to develop pale or discoloured leaves, discontinue using greywater in that area.
Look on detergent labels for information about whether it’s suitable for greywater usage. Product labels may say ‘Greywater safe’ or ‘Greywater friendly’. Some laundry detergent manufacturers recommend only using washing machine rinse water to irrigate the garden and not the wash cycle water, so this needs to be taken in account when using greywater. www.lanfaxlabs.com.au provides information on the suitability of some detergents when using greywater.
And add Yates Greywater Fertiliser to greywater to help minimise the negative effects of soaps and detergents on soil quality.
Additional information on greywater