Question: how far down does water go into the earth

Matt Bower answered on 5 Nov 2018:

That is a really interesting question and the honest answer is we are still finding out. Water we use for drinking comes from up to about 100-200m below ground (although usually it’s much shallower). As you go further down the water is very old and often has a lot of minerals dissolved in it meaning you wouldn’t want to drink it. Sometimes this deep water has hydrogen sulphide in it so it smells of rotten eggs! Deep water may also be hot because as you go down the rocks get hotter.
Recent research has suggested there may be water even deeper down, below the Earth’s crust and into the mantle. If it’s there, this water must be very hot indeed.