Drinking water or potable water is water pure enough to be consumed or used with low risk of immediate or long term harm. In most developed countries, the water supplied to households, commerce and industry is all of drinking water standard, even though only a very small proportion is actually consumed or used in food preparation. Typical uses include washing or landscape irrigation.
Reduction of waterborne diseases is a major public health goal in developing countries.
Water has always been an important and life-sustaining drink to humans and is essential to the survival of all organisms. Excluding fat, water composes approximately 70% of the human body by mass. It is a crucial component of metabolic processes and serves as a solvent for many bodily solutes. The United States Environmental Protection Agency in risk assessment calculations assumes that the average American adult ingests 2.0 litres per day. Drinking water of a variety of qualities is bottled.
Chemical and other contaminants
Muddy river polluted by sediment. Photo courtesy of United States Geological Survey.Contaminants may include organic and inorganic substances.
Organic water pollutants include:
Disinfection by-products found in chemically disinfected drinking water, such as chloroform
Food processing waste, which can include oxygen-demanding substances, fats and grease
Insecticides and herbicides, a huge range of organohalides and other chemical compounds
Petroleum hydrocarbons, including fuels (gasoline, diesel fuel, jet fuels, and fuel oil) and lubricants (motor oil), and fuel combustion byproducts, from stormwater runoff
Tree and bush debris from logging operations
Volatile organic compounds (VOCs), such as industrial solvents, from improper storage.
Chlorinated solvents, which are dense non-aqueous phase liquids (DNAPLs), may fall to the bottom of reservoirs, since they don’t mix well with water and are denser.
Polychlorinated biphenyl (PCBs)
Various chemical compounds found in personal hygiene and cosmetic products
A garbage collection boom in an urban-area stream in Auckland, New Zealand. Inorganic water pollutants include:
Acidity caused by industrial discharges (especially sulfur dioxide from power plants)
Ammonia from food processing waste
Chemical waste as industrial by-products
Fertilizers containing nutrients–nitrates and phosphates–which are found in stormwater runoff from agriculture, as well as commercial and residential use
Heavy metals from motor vehicles (via urban stormwater runoff) and acid mine drainage
Silt (sediment) in runoff from construction sites, logging, slash and burn practices or land clearing sites
Macroscopic pollution—large visible items polluting the water—may be termed “floatables” in an urban stormwater context, or marine debris when found on the open seas, and can include such items as:
Trash or garbage (e.g. paper, plastic, or food waste) discarded by people on the ground, along with accidental or intentional dumping of rubbish, that are washed by rainfall into storm drains and eventually discharged into surface waters
Nurdles, small ubiquitous waterborne plastic pellets Shipwrecks, large derelict ships.