The Quest/Spoiler-free hints

Drink water
If you run out of water, you and Gorn will die of thirst. It is therefore necessary to buy a waterskin.

You can refill the waterskin at various locations.
 * Central Balema: there is a lake to the west, before the forest.
 * West Balema: there is a fresh water pond at the end of a southwards road.
 * North Balema: you can refill the waterskin in the river, near the bridge or the waterfall; there is also another water source, harder to find.