Greywater is reusable wastewater from washing machines, showers, baths and basins. It's a relatively easy and safe source of water to access and use. Because it's a good source of important nutrients for many plants, it can be a source of water for irrigation all year round.
Using greywater is perfectly safe if it is used properly. However, if it isn't used properly it has potential to spread disease around your home and elsewhere. For example, infection can occur if untreated greywater is stored or used in a way that birds, insects, pets or children can come into contact with it.
Manual bucketing is the cheapest way to use greywater. It means simply collecting water in a bucket from your washing machine or shower and using it to water your garden. You don't need permission to do this. However, don't store or keep the collected greywater for more than one day. This avoids the risk of spills and bad odours.
To prevent greywater running into neighbouring properties, don't use manual bucketing when it's raining or when the soil is already saturated.
Greywater diversion devices are simple systems. They divert greywater to a small holding tank and then to an irrigation system that's below the soil surface. These systems should be self-draining so that greywater isn't stored for more than a day. They also have a valve to make it is easy to divert greywater directly to the sewer when it’s raining or when the soil is saturated.
There's a range of diversion solutions available, so make sure you choose the one that best meets your needs. Consider cost, durability, ease of use, ease of installation and maintenance. NSW Health maintains a register of accredited greywater diversion devices.
Greywater treatment systems mean you can use all the greywater your home generates regardless of the weather. After treatment, the greywater is clean enough to be stored.
Treated greywater should be almost colourless and it shouldn't have a bad odour. It is not safe to drink. However, you can use treated greywater to:
Greywater treatment systems are available from many suppliers. The Environmental Health team at NSW Health has accredited these suppliers.
Some soaps and detergents are harmful for your garden. An independent laboratory, Lanfax Laboratories, has researched popular laundry detergents and how they affect plants and soil.