Water treatment is, collectively, the industrial-scale processes that makes water more acceptable for an end-use, which may be drinking, industry, or medicine. Water treatment is unlike small scale water sterlization that campers and other people in wilderness areas practice. Water treatment should remove existing water contaminants or so reduce their concentration that their water becomes fit for its desired end-use, which may be safely returning used water to the environment.

The processes involved in treating water for drinking purposes to provide a safe source of water supply may be solids separation using physical processes such as setting and filtration and chemical processes such as disinfection and coagulation.

For most people, the term “water treatment” refers to potable water production from raw water, whereas “wastewater Treatment” refers to the treatment of polluted water, where the pollution could be from human waste, industry, agricultural waste or other sources of pollution.

Water purification is the removal of contaminants from untreated water to produce drinking water that is pure enough for the most critical of its intended uses, usually for human consumption. Substances that are removed during the process of drinking water treatment include suspended solids, bacteria, algae, viruses, fungiu,minerals such as iron,mangenese and sulfur, and other chemical pollutants such as fertilisers.

Measures taken to ensure water quality not only relate to the treatment of the water, but to its conveyance and distribution after treatment as well. It is therefore common practice to have residual disinfectants in the treated water in order to kill any bacteriological contamination during distribution.

World Health Organisation  (WHO) guidelines are generally followed throughout the world for drinking water quality requirements. In addition to the WHO guidelines, each country or territory or water supply body can have their own guidelines in order for consumers to have access to safe drinking water.