Reclaimed water is treated wastewater which can be used in nonpotable applications, meaning situations in which the water will not be consumed by people or animals. Many regions around the world promote the use of reclaimed water to conserve water supplies, ensuring that access to potable water will always be available. In some areas, reclaimed water may be subsidized by regional agencies to make it a low-cost alternative to using potable water.
There are a number of uses for reclaimed water. For example, it can be used to irrigate landscaping and golf courses. It can also be used in ornamental water features like fountains, and for things like hosing down buildings and sidewalks, suppressing dust, and fighting fires. Essentially, any situation in which water will not be consumed is appropriate for reclaimed water, with potable water being reserved for cooking, bathing, irritating edible plants, and washing clothes.
Water treatments create reclaimed water by treating sewage, removing the solids and filtering the resulting water to remove as much material as possible. The water is not considered potable because it has not been treated for every potential pathogen, and because many water treatment agencies regard sewage as inherently dangerous. However, using reclaimed water is beneficial to the aquifer, as potable water is not wasted for situations in which reclaimed water could be used instead.
By conserving potable water, communities use water more efficiently, ensuring that ample water supplies are available. Protecting the aquifer can be especially valuable in areas experiencing land subsidence or water shortages as a result of a depleted aquifer. In areas where people must import water, using reclaimed water also cuts down on water costs, by reducing the amount of water which needs to be imported. This makes reclaimed water a popular option in desert areas.
While reclaimed water is not technically potable, it sometimes enters the potable water supply. For example, reclaimed water may filter into the aquifer after being used for irrigation, or it may be released into a river which is used to feed a water supply system. In these cases, the reclaimed water is generally believed to be rendered safe through the use of water treatment and filtration.
You may hear reclaimed water referred to as recycled water, or treated wastewater. In regions where reclaimed water is in wide use, people often encounter signs near streams, culverts, and dams indicating that the water there is unsafe to drink or play in, because it is reclaimed.