Thirst

Thirst is displayed above your hunger bar. If your thirst bar runs out, you will start to take damage.

You can SHIFT+RightClick with an empty hand to drink from water blocks or the rain.

You can also drink from a Canteen and water bottles.

Drinking regular water may give you the Thirsty effect, so making Purified Water or Juice is a good idea.

You can smelt water bottles or water buckets in a furnace to get purified water.

You can gather rain with a Rain Collector, and you can retrieve it with a canteen, bucket, or bottle.

You can also use a Charcoal Filter with a canteen or water bottle to purify its contents.

Thirst, like hunger, has saturation, so more valuable drinks will last longer. This is shown as gold around the thirst bar.