This paper explores the conversion of raw seawater into drinking water from a religious water literacy (RWL) perspective. RWL is here defined as a socially just water literacy that is based on the respect for the dignity of life of all living beings on the Earth. It discusses the importance of sustainable water sources and proposes purification methods. That is, the study aims to show a brief outline of the drinking water source (inland waters; mainly river water) and their purification technologies in recent times and today and propose the purification method (Freezing-Thawing-UV method) in case of taking the seawater as the source. And, it emphasizes the need for dialogue and cooperation between countries in order to proceed. The paper also discusses the relationship among religion, culture, and civilization, and highlights the similarities between Marx's historical materialism and Umesao's ecological view. It further discusses the importance of water purification technology, separation methods, and the potential for seawater as an energy source. The paper concludes by discussing the importance of dialogue, communication and understanding environmental decision-making. In order to carry them forward, it is convinced that citizens in the world are nothing but people with self-awareness of "Bodhisattvas of the Earth" as identities. As a result, the new findings that suggest the possibility of raw seawater into drinking water from a religious water literacy perspective through the lens of Kawakatsu's maritime view have been obtained.