Around 50% of our potable water is used for non-potable applications such as industrial processes, garden irrigation, toilet flushing, car washing, and swimming pool top-up etc.
Urban water is mostly available from the reticulated mains supply that needs to meet water quality standards for potable supply. This reticulated water source has passed through sophisticated water treatment plants and has generally been pumped over long distances. Mains distributed water is often utilised in applications where the quality of the treated water is far higher than is required.
In many of these situations, rainwater harvesting is an adequate supply for localise water needs. It is generally well mineralised and oxygenated. It also has the benefit of locally available.
Agriculture and irrigation in various forms accounts for around 70% of our water usage in rural areas. The major source for this water is in aquifers, lakes or dams. These sources rely on rains, and often flooding rains, to replenish, initially through run-off into ponds, dams, rivers and lakes, and then infiltration.
Stormwater harvesting is another crucial source and consists of rainfall that has reached the ground. Once on the grount the water starts to collect contaninants and requires a disciplined treatment train filtration process before being available for storage.
The stormwater is an ideal and source for the 70% of non-potable applications. It is also the case that future water needs will utilise stormwater harvested for treatment to drinking water quality standard to supplement the reticulation systems that cannot met the increasing demand for water.
There is another water source, greywater generally from household drainage or blackwater from sewer pipe systems mining that are becoming a valuable source of water for non-potable applications, however it does require intense treatment because of the nature of the contamination and volumes need to make this process economically viable. Recycled sewage water can supplement the water source needs but remains as a lesser grade water source for particular applications.
What alternate water sources can you consider beyond reliance on highly treated reticulated mains water?