Interesting finding about water on Mars. Polar layered deposits hold most of the known water on Mars, though other areas of the planet appear to have been very wet at times in the past. The south polar layered deposits alone are the size of the US state of Texas.

BBC News
March 16, 2007
Paul Rincon, Science reporter, BBC News, Houston

Polar water 'would blanket Mars'
Enough water is locked up at Mars' south pole to cover the planet in a liquid layer 11m (36ft) deep.

The Mars Express probe used its radar instrument to map the thickness of Mars' south polar layered deposits.

Analysis of the Marsis radar data shows that the polar deposits consist of almost pure water-ice. Read more...