Water was Used by Jews for Legal Purification
Source: TTT
Exodus 29:4
Then present Aaron and his sons at the entrance to the Tent of Meeting and wash them with water.
Hebrews 9:10, 19
They consist only in food and drink and special washings—external regulations imposed until the time of reform. / For when Moses had proclaimed every commandment of the law to all the people, he took the blood of calves and goats, along with water, scarlet wool, and hyssop, and sprinkled the scroll and all the people,