The Shinto purification ritual involving water is called misogi.
Misogi is a ritual washing or immersion intended to remove kegare, a condition of ritual impurity. Traditionally, practitioners may enter the sea, a river, a lake, or a waterfall; some communities perform the rite before sunrise or after preparatory prayers, fasting, breathing exercises, or the use of salt. Full-body immersion is the defining feature of the practice.
Misogi is closely related to harae, the broader Shinto category of purification. Harae may involve a priest waving a haraigushi, reciting purification prayers, or using salt and water, while misogi specifically emphasizes cleansing through water. Oharae means “great purification” and commonly refers to a formal purification ceremony, often held twice yearly.
The mythological background is linked to Izanagi, who purified himself after returning from Yomi, the land of the dead. In the story, various kami emerged as he washed different parts of his body. A brief hand-and-mouth rinse at a shrine is called temizu, so it is related to misogi but is not usually the same full-body ritual.