Water is a common chemical substance that is essential for the survival of all known forms of life. In typical usage, water refers only to its liquid form or state, but the ...
http://en.wikipedia.org/wiki/Water

Water (H 2 O, H OH) is the most abundant molecule on Earth 's surface, composing of about 70% of the Earth's surface as liquid and solid state in addition to being found in the ...
http://en.wikipedia.org/wiki/Water_%28molecule%29

US federal agency responsible for protecting and improving water quality. Details of national water programs, online library, local information, laws, and kids page.
http://www.epa.gov/OW/

What are water's physical and chemical properties from the U.S. Geological Survey's Water Science for Schools site.
http://ga.water.usgs.gov/edu/waterproperties.html

Home page for water resources information from the US Geological Survey ... Science In Your Watershed : Of Current Interest... USGS Investigations on Ground-Water Trends Released ...
http://water.usgs.gov/