Which planets have water?
To answer this question you first need to specify three things:
- Are you asking specifically about liquid water, or are you including solid water (ice) and gaseous water (vapour)?
- Are you asking about water on the surface, or are you including water below the surface and in the atmosphere?
- Are you talking about the eight planets in our solar system, are are you including dwarf planets and/or exo-planets (from other solar systems).
Earth is the only planet in our Solar System that has stable bodies of liquid water on the surface. On any other planet (or moon, asteroid, etc.), liquid water would immediately evaporate or freeze. There are several places in the Solar System that could potentially have underground rivers, lakes or even enormous oceans. There are also numerous planets, moons and comets that have water in different states, mainly ice but sometimes vapour.
Water on planets in the Solar System
Mercury: Frozen water. More info
Venus: Basically no water at all. More info
Earth: Lots of water in all forms (liquid, ice, vapour).
Mars: Ice, trace amounts of vapour, possibly some liquid water underground. More info
Jupiter: Water in frozen and vapour form.
Saturn: Water in frozen and vapour form.
Uranus: Frozen water.
Neptune: Frozen water.
Do any dwarf planets have water?
Pluto: Frozen water.
Ceres: Some frozen water, possibly underground liquid water.
What about planets in other solar systems (exoplanets)?
We don't really know. We assume that many exoplanets will have water but at this stage we don't have any way to confirm this.