"You drink some water from the Pond"

If you become Thirsty, you can quench the thirst by drinking water from bodies of water such as Ponds, Water Pumps or other sources of water.

Note that you might need to drink more then once to completely cure the thirst - check your character sheet (TAB by default) to make sure you have drank enough (the "Thirsty" tab should disappear from there)