FACTBOX-Water everywhere, but not clean enough to drink

(Reuters) - Following are some facts about strains on the world's freshwater supplies:

OVERVIEW:

* Seventy percent of the world's surface is covered by water but 97.5 percent of that is salt water. Of the remaining 2.5 percent that is freshwater, 68.7 percent is frozen in ice caps and glaciers. Less than one percent is available for human use.

* More than 1.2 billion people, about a fifth of humanity, lack access to safe drinking water, according to U.N. data. About 2.6 billion, or 40 percent, have no access to sanitation. About 71 percent have no connection to a public sewerage system.

* Forty-four percent of the world's population live in areas affected by high water stress and the figure is likely to rise to 47 percent by 2030 because of factors including global warming and a rising population.

* Agriculture absorbs 74 percent of all water taken by humans from rivers, lakes, aquifers and wetlands against 18 percent for industry and 8 percent for municipalities.

DRINK AND HEALTH:

* Governments set a Millennium Goal in 2000 of halving the proportion of people with no access to safe drinking water by 2015. The goal is within reach, according to a 2007 U.N. review, but the world is lagging in a linked goal of halving the proportion with no access to sanitation.

* Diarrhea and malaria are the main water-related diseases, with most deaths among young children. Every 20 seconds a child dies because of poor sanitation -- or 1.5 million a year. Every year more than 200 million tonnes of human waste go uncollected.

* Achieving the twin 2015 drinking water and sanitation goals will require spending of $11.5 billion extra a year. Every dollar spent on sanitation brings an average benefit of $7, mainly because of better health.

AGRICULTURE/INDUSTRY

* The amount of water needed for crop production will rise 60-90 percent by 2050.

* A calorie of food needs about a liter of water to produce -- typical food consumption is 3,000 calories a day per person, or 3,000 liters of water. A kilo of grain takes 500-4,000 liters, a kilo of industrially produced meat 10,000 liters.

* Rising production of biofuels -- from crops such as maize, soybeans or sugarcane -- could complicate efforts to feed the world and may add strains to irrigation.

* Industry can often cut its water demand by 40-90 percent, given proper incentives, according to U.N. data.

CLIMATE CHANGE