John 2:6

The Jews washed before eating to cleanse themselves from the defilement of contact with Gentiles and other ritually defiling things more than from germs. They needed much water since they washed often (cf. Matthew 15:1-2; Mark 7:3-4). Each pot held two or three measures (Gr. metretes), namely, between 20 and 30 gallons. Their combined capacity would have been between 120 and 180 gallons of liquid. Stone pots did not absorb moisture and uncleanness as earthenware vessels did, so they were better containers for water used in ceremonial washings.