This paper analyzes water-related idiomatic expressions in Korean, which were not well dealt with in prior research, by comparing them with Chinese and English, and identified the cultural background underlying the generation of idiomatic expressions. Among the idiomatic expressions related to water, idiomatic expressions created by the idea of water’s liquidity existed in both Korean, Chinese, and English. In addition, idiomatic expressions related to the negative effects of the idea that water can cause natural disasters exist in all three languages. However, there were differences in idiomatic expressions related to this between Asians who showed an attitude of acceptance towards the providence of nature and Westerners who considered nature an object of human exploration. This paper analyzes these differences as images of water appearing in the Tao-Te Ching (道德經) and the Bible that influenced Eastern and Western thought. Most of the water described in Tao-Te Ching is static water, such as in rivers and lakes. On the other hand, water in the Bible is mostly described as ocean water, and water is closely linked to an object and adventure that humans must conquer. This has created a difference in the view of water in Eastern and Western cultures, and this has been reflected in the idiomatic use of language. While analyzing these water-related idiomatic expressions, this paper was able to examine the differences between the common cognitive and cultural backgrounds of humans reflected in language.