Mimas, the smallest and innermost of Saturn‘s major moons, is believed to generate the right amount of heat to support a subsurface ocean of liquid water
https://www.space.com/saturn-moon-mimas-stealth-ocean-world
Unfortunately the “stealth ocean” is only a few million years old, not nearly enough to harbor life.
But it demonstrates the fact that water may in fact be common in space, opening the possibility of finding life on celestial bodies with older (much older) water sources.
(FYI: Mimas orbits Saturn once every 22 hours, and is affected by tidal forces from Saturn that appear to have melted part of its icy surface.)
M Thomas Apple Author Page 