Decanter of Endless Water

From the introduction:

In desert communities or to the wandering adventurer, there is no magic item more precious to their continued survival than the decanter of endless water. All living creatures need water to survive and the decanter has served as a lifeline for entire tribes of desert dwellers and others who seek out an existence in arid lands. While the decanter of endless water has had many uses over the years since its creation, it was an act of sacrifice for the survival of others that created the first decanter and has gifted the desert and adventuring world with a much needed renewable source of fresh water.