Water is essential for our life. We need water to quench our thirst, to wash and refresh ourselves, to prepare food. Without water, life is not possible. It is for this reason that the Church uses water as a symbol of new life. To receive this new life, we are baptized through the water and the Holy Spirit. Jesus identifies with the Living Water. With the water that cleans, with the water that quenches thirst. In baptism, water represents our personal renewal and the rejection of sin.
When we use holy water we do it to renew that blessing that we have received since our baptism. Especially during Easter time we use holy water as a sign of that new and risen life in us. Today we tell the risen Jesus to come to us and grant us purification with holy water, a sign of Easter. Using holy water as a sign that we have died to our sin and received new life through his resurrection.