Usually, regular water is taken from the tap and then blessed either at Mass or afterward.
Holy water is blessed by an ordained minister. There are no specific regulations concerning the drinking of blest water; however, sometimes the water sits in a holding tank for days, and therefore it wouldn’t be advisable to drink. Holy water is a sacramental, meaning it is related to a sacrament. Baptism employs the usage of holy water to confer the sacrament.
In the blessing of water at baptisms, the prayer traces the long history of water as a purifying and cleansing substance. It mentions, for instance, the parting of the Red Sea in which the Israelites were lead out of slavery. Through the water of baptism, Jesus leads us out of the slavery of sin.
The usage of holy water outside of Mass has many different forms. Priests use holy water to bless people, objects, and places. At the beginning of Mass, holy water is sprinkled on the people. Holy water, when consciously used, removes venial sins. When objects are blessed with holy water by a priest or deacon they become reserved for sacred use and should be disposed of in a dignified way. When palms are blessed on Palm Sunday, they cannot be thrown into the waste paper basket after they become old and withered; rather, they may be buried or burned.
The verse from the Old Testament Exodus 12:22 refers to hyssop. Hyssop was a plant used by the Israelites for sprinkling the blood of the Passover lamb on the lintels of Jewish homes. Hyssop had medicinal properties and was used for healing. In the New Testament, holy water is referred to as hyssop. The blood of the Lamb, Jesus Christ, which was poured out on Good Friday, is passed to our souls through the waters of baptism. When holy water is used at Mass, it reminds the faithful of the saving blood of Jesus.
Many people store and use holy water in their homes. Homes can be seen as little churches. When we take holy water before leaving home, this reminds us of the rich blessings God bestows on His people.
Often, people bless their homes during storms to invoke God’s blessings in time of calamity. When Catholics enter or leave church, they take holy water by their fingers and make the sign of the cross over themselves.
When sprinkled at Mass or at a blessing, they make the same sign of the cross. Again, they are reminded of the rich blessings of God.