Researchers have discovered free flowing water in a deep reservoir at the bottom of an old zinc mine in Canada. The water contains traces of the gas xenon which has allowed scientists to estimate its age; the water has been trapped beneath the earth for roughly 1.5 billion to as much as 2.5 billion years. It has the right amount of hydrogen and other gases to allow it to support microbial life. Test to that affect are ongoing
What this means of course is that water beneath the planet of Mars could still contain life.