Seems our probes are finding water ice in lots of places (Mercury, Mars, Enceladus, etc.).
Hmm, how do I put this... All of Saturn's moons basically are nothing but ice a good way down to the core. Except that at those temperatures for all intents and purposes it behaves as rock.
...Not just ice, but probably liquid water for much of Enceladus.
It's also possible that some of these moons are some sort of rock/ice mixture.