How many planets have the same amount of water as the earth?

Answer 1

If you mean liquid water, then the Earth is the only planet.

Mars has water ice in abundance but if melted, would probably not be anywhere near as plentiful as Earth.

NASA calculates that if all the water ice was melted, Mars could be covered by water to a depth of 11m.

So, as of 2010, no known planets have the same amount of water as Earth.

Answer 2

Based on current knowledge, Earth is unique in our solar system in terms of the amount of water it has, both in liquid and frozen form. Other planets or celestial bodies may have water in different states, but not in the same quantity as Earth.