Definition: Potable Water means drinking water. The word 'Potable' comes from the Latin, 'to drink'. If you see the term/words 'potable water' it means the water is safe to drink. Portable water isn't pure water - it's water from the ground or it's the water that comes out of a tap or the water in bottled water - all of these have some minerals and salts in them from the earth. This is fine, as long as these are in low quantities - if you look at the label of bottle of water it says how much of each there is so it's still safe to drink. The other thing we need to be careful of is that the water doesn't contain harmful bacteria which could make us ill so it might still have to be tested to make sure it's safe to drink.