Mystery haze appears above Ceres' bright spots : Nature News & Comment
The article says Ceres is "at least" 1/4 water. It's also about 1,000 km across. If I had time, I'd work out the weight and volume of ice, then. But I see a report from 2005 says it might be more fresh water than on all of Earth.
That could go a long way towards making the Moon a livable place. Got to get Ceres there first, though.
But what's the diameter of the Moon? Only 3,500 km? I imagined it would be bigger than that. Well, I wouldn't recommend smashing Ceres into it, then. Although I guess it could be a way of making some nice, ice rings around the planet.