Although covering some 70% of the Earth's surface, most water is saline. Freshwater is available in almost all populated areas of the earth, although it may be expensive and the supply may not always be sustainable. Sources where water may be obtained include: ground sources such as groundwater, hyporheic zones and aquifers. precipitation which includes rain, hail, snow, fog, etc. surface water such as rivers, streams, glaciers biological sources such as plants. the sea through desalination water supply network Spring water is groundwater that rises to the ground surface. Springs are often used as sources for bottled waters.[14] Tap water, delivered by domestic water systems in developed nations, refers to water piped to homes and delivered to a tap or spigot. For these water sources to be consumed safely they must receive adequate treatment and meet drinking water regulations.[15] The most efficient way to transport and deliver potable water is through pipes. Plumbing can require significant capital investment. Some systems suffer high operating costs. The cost to replace the deteriorating water and sanitation infrastructure of industrialized countries may be as high as $200 billion a year. Leakage of untreated and treated water from pipes reduces access to water. Leakage rates of 50% are not uncommon in urban systems.[16] Because of the high initial investments, many less wealthy nations cannot afford to develop or sustain appropriate infrastructure, and as a consequence people in these areas may spend a correspondingly higher fraction of their income on water.[17] 2003 statistics from El Salvador, for example, indicate that the poorest 20% of households spend more than 10% of their total income on water. In the United Kingdom authorities define spe

ding of more than 3% of one's income on water as a hardship.[18] The World Health Organization/UNICEF Joint Monitoring Program (JMP) for Water Supply and Sanitation [19] is the official United Nations mechanism tasked with monitoring progress towards the Millennium Development Goal (MDG) relating to drinking-water and sanitation (MDG 7, Target 7c), which is to: "Halve, by 2015, the proportion of people without sustainable access to safe drinking-water and basic sanitation".[20] The JMP is required to use the following MDG indicator for monitoring the water component of this: Proportion of population using an improved drinking-water source. According to this indicator on improved water sources, the MDG was met in 2010, five years ahead of schedule. Over 2 billion more people used improved drinking water sources in 2010 than did in 1990. However, the job is far from finished. 780 million people are still without improved sources of drinking water, and many more still lack safe drinking water: complete information about drinking water safety is not yet available for global monitoring of safe drinking water. Continued efforts are needed to reduce urban-rural disparities and inequities associated with poverty; to dramatically increase coverage in countries in sub-Saharan Africa and Oceania; to promote global monitoring of drinking water quality; and to look beyond the MDG target towards universal coverage.[21] In the U.S, the typical single family home uses 69,3 gallons (262 litres) of water per day. This includes (in decreasing order) toilet use, washing machine use, showers, baths, faucet use, and leaks. In some parts of the country there are water supplies that are dangerously low due to drought, particularly in the West and the South East region of the U.S.