Fresh water

Fresh water (also 'freshwater' or 'fresh-water') is water that does not have a lot of salt in it. It usually means water from the lakes, rivers, snow, and ice. These types of water do not have much salt in them. It also can mean water that people can drink. The oceans and seas are made up of salt water, which people cannot drink.   

People cannot drink all fresh water, because it might be contaminated. It might have harmful bacteria in it, or it might be poisonous because of chemicals it contains. Water from a tap has been tested and treated so that it is safe to drink. This applies to most countries, but in some places the water needs to be boiled first to kill the germs and drunk after it has cooled down.

Fresh water that people can drink safely is called potable water. Desalination can turn salt water into drinkable water.

What causes water scarcity is the mismatch between fresh water demand and availability. What this means is that there is fresh water available, but not always where it is most needed.S.L. Postel, G.C. Daily & P.R. Ehrlich 1996. Human appropriation of renewable fresh water. Science 271, 785–788. H.H.G. Savenije 2000. Water scarcity indicators: the deception of the numbers. Physics and Chemistry of the Earth B 25, 199–204.

In many countries the water used by people is recycled water. People pay for water supply which is safe to drink. Water theft also happens. Thames Water thinks water loss by theft is a big problem. Waste water (sewage) is treated to purify the water. That is why people are charged for the supply of pure water.

 Related pages 
 Sewage treatment
 Water cycle
 Water scarcity
 Water supply system
 Salinity
 Snow

 References 

Category:Water