The ESA Herschel space observatory has noticed that Enceladus is raining water vapor onto Saturn itself. We have known for some time that there were geysers on the surface of Enceladus. The magnitude of the water loss was not fully understood though. Now based on observations it is claimed 250 kg / s of water is being lost to Saturn. The total mass of Enceladus is estimated at 1E20 kg which means, if my math is right, the total mass of the moon would take 12.6 billion years to deplete at that rate. Naturally Enceladus is not 100% water, no one really has a handle on how much water is inside Enceladus. If it was 1% water it would take 126 hundred million years to deplete the water. That is a relatively short time according to modern planetary theory.
Where did the water come from ? Well its starting to look like water is not that scarce in the solar system or in deep space. We recently believed we found traces of water on the moon. In 2001 we found what is believed to be large clouds of water vapor in deep space around the star IRC+10216. If that is true then, in my opinion, it may turn out water is not scarce at all, but that surface water is scarce.
That is a rather startling conclusion.