WATERPOT (Gr. hydria). An earthen jar for carrying or holding water, either for drinking (John.4.28) or for purifying purposes (John.2.6-John.2.7). The latter was large, holding eighteen to twenty gallons (sixty-nine to seventy-seven l.). NIV has “water jar.”

International Standard Bible Encyclopedia (1915)

An earthen vessel, or jar, for carrying or holding water (in the Septuagint for kadh, "jar," or "pitcher"). It was usually carried by women upon the head, or upon the shoulder (Joh 4:28). Pots of larger size, holding eighteen or twenty gallons apiece, were used by the Jews for purposes of ceremonial purification (Joh 2:6).