After analyzing how much water there is on our planet and posting about it here a few days ago, I researched about water in the rest of the solar system. I knew that both Europa (a moon of Jupiter) and Titan, a moon of Saturn, both have large amounts of water.
So I found the above picture and article. Scientists estimate that Europa has twice as much water as Earth, and Titan eleven times as much.
The respective blue bubbles and the moons and the Earth are all to scale.