Holy water is a sacramental. Properly called sacred signs since Vatican II, these consist of ordinary, everyday objects, prayers or actions designated as sacramentals and blessed by the Church. Through the Church's intercession, they are meant to bring God's blessings upon us.
Although the names, sacraments and sacramentals, are similar, we must be careful not to equate the sacramentals with the sacraments as, I've noticed, sometimes is done in comments in Catholic publications.
Theologians teach us that sacramentals are operative only through the prayer of the Church while the sacraments bring God's grace through the power given them directly by Christ. For example, an individual who is not properly disposed actually does receive the body and blood of Christ in the Eucharist, although perhaps not the fullness of grace that God intends.
The number of sacramentals is determined by the Church and is unlimited while the sacraments are few in number. Sacraments are accessible to us at all times since they can be used by all without the need of a priest or bishop. They bring a sacred dimension into everyday actions and help strengthen one's faith life. They are a popular way of expressing one's devotion.
As Catholics, the Eucharist and the sacraments are the high points of our lives, to which and from which everything else flows. For a number of centuries, many of our devotions and sacramentals had taken centre stage sometimes being practised in a superstitious way. Vatican II re-connected these to their base in the Eucharist.
Although both use ordinary objects, signs or actions, it is important to remember that sacraments are essential to Catholic belief and practice. The practice and choice of sacramentals is optional. One person may use one sacramental frequently while not using others. Another person may prefer using many sacramentals or none at all.
Water is one of the most fitting of sacramentals. Water's symbolism as a sign of purification is clearly evident by its use in the rituals of many religions. It comes to us from Jewish practices. Among the mention of its use in the Old Testament is in the Book of Numbers (8:7), when God tells Moses to sprinkle water on the Levites to purify them. John the Baptist's baptism of repentance was a sign of purification of sin. Jesus, too, though without sin, chose to be baptized by John in the water of the Jordan River.
During the first centuries of Christianity, water used for Baptism was not blessed but gradually an elaborate ritual was developed for the Easter Vigil. This blessing has special meaning for us today because of the re-introduction of Baptism during the Easter Vigil. Water can be, and is, blessed at other times also.
Water and other sacra-mentals are blessed with prayers for protection from evil spirits and other calamities, as well as blessings of various kinds such as forgiveness and healing. Placed at the entrance to the church, it provides us with the incentive to renew our baptismal commitment and be reminded of the holiness of the building we are entering and the actions that will take place there.
Sprinkled on the congregation at the beginning of Mass, it is used as the penitential rite and becomes a tangible sign of purification needed to listen to the word of God and celebrate the Eucharist. Used to bless our homes or sprinkled at the approach of a storm, it has been known for God's protection. Blessing the sick and dying, it comforts and heals.
We must remember that holy water is not magic water. It is ordinary water blessed by the Church and set aside to be used in faith. Blessing ourselves with it at any time brings God's presence and love to our minds. Like other holy objects and sacred signs, it can punctuate our busy lives and so help us live with and for God.