CCC 1238
© Libreria Editrice Vaticana Source: vatican.va
The baptismal water is consecrated by a prayer of epiclesis (either at this moment or at the Easter Vigil). the Church asks God that through his Son the power of the Holy Spirit may be sent upon the water, so that those who will be baptized in it may be "born of water and the Spirit." Jn 3:5.
Read the full chapter 1. The Sacraments of Christian Initiation ¶1212–1419