It is said that the next wars will not be fought over oil, but rather over a far more precious resource, water. Changing weather patterns have caused enormous droughts in some parts of the world, Australia is one example, but regional examples abound, for instance California has experienced water restrictions in the past, as have many other parts of the United States. This has lead many homes in drought prone areas to install greywater treatment systems.
One of the first casualties of water restrictions are gardens. As a first step authorities usually restrict watering to certain times and amounts. If the drought worsens watering gardens is usually banned outright. Greywater is water that has been used for bathing, washing dishes or doing laundry and can consist of up to 80% of the water used by a household. Water from some portable and basement dehumidifiers are also classified as greywater. By installing greywater treatment systems households allow for greywater recycling. Once the greywater has been treated it can be used for gardening purposes, or for other tasks like washing the car. Recycled greywater is generally not suitable for human consumption. Dwindling levels of fresh water have also caused authorities in some parts of the world to investigate the use of greywater for large scale irrigation.