When God says that He created man from water, it does not imply that man was created solely from water. It actually means that water is one of the building blocks of the human body. Majority of the human body is made up from water, in other words H2O.
Modern science tells us that the human body contains of up to 60% of water on average. This was not a known fact 1,000 years ago, when the equipment and mechanisms necessary to carry out tests were not available.
God created every [living] creature from water. Some of them go on their bellies, some of them on two legs, and some on four. God creates whatever He wills. God has power over all things
…and We made from water every living thing? So will they not believe?
And it is He who has created from water a human being and made him [a relative by] lineage and marriage. And ever is your Lord competent [concerning creation].
How could something revealed 1,400 years ago contain such information. It could only have happened if it was divine, i.e. sent by God Himself in His Own words. All living things consist of water, even trees and twigs have water, it is just a matter of what percentage water makes up a mentioned life form.
“The water in you” Retrieved from, http://water.usgs.gov/edu/propertyyou.html, 1 July 2014
“Water in your body” Retrieved from, http://www.nestle-waters.com/healthy-hydration/water-body, 1 July 2014
“How water works” Retrieved from, http://science.howstuffworks.com/environmental/earth/geophysics/h2o3.htm, 1 July 2014