Water is essential in the Thai-Tai way of life. Thai people in Thailand as well as Tai peoples outside Thailand depend on water for agriculture, domestic daily uses, transportation and recreation. This paper is a result of an in-depth study of the relationship between water, beliefs and literary traditions of the Thai and some ethic Tai groups. The findings reveal that the Thais and the Tais have religious beliefs involving water concerning four important water beings: first, the water spirit known as sua nam (เสื้อน้ำ); second, the water serpent known as nguek (เงือก); third; the great serpent or naga (นาค); and fourth; the river of the dead. 

Of the four beliefs, the first two concerning the water spirit and nguek could date back to very ancient times and are common among several Tai ethnic groups. They provide a clear indication that the Thais and Tais hold nature in high reverence and awe. With the notion that nature is regulated and protected by a life-force, a rite to ask permission to use water from the spirit is almost always staged prior to the actual use. While Thai and Tai people recognize the benevolence of water and perceive it in life-form, they are fully aware of the precariousness of nature. The pervading influence of the mythical naga can be seen in Thai art, and the naga character in literature, folktales, legends concerning city building, religious architecture, and in rituals. The role of the naga in Thai and Tai narratives has been modified or adapted in various local traditions. 

River and water motifs are woven into Thai-Tai literature in both form and content. Impromptu recitation of sakawa ( a form of folksong), and Krab hey Rua are related to waterway in form; while idioms and metaphors, prays of characters in dilemma, waterborne society in a drama or play, and marine warfare, etc. are in content.