Holy Water carries a blessing and an indulgence.
Holy Water remits venial sins.
We are to be detached even from venial sins to gain any indulgence when we pray.
Holy Water fonts are placed at each entrance of a church to remit venial sins (purify us) before entering into the presence of God, and to be used at our exit to bless us on our journey.
The custom of Holy Water fonts, especially at the entrances of our homes, is probably one of the oldest customs/traditions of the church. The first Christians started it as a carryover from the Mazuzah of their previous Jєωιѕн faith.
Catholics bless themselves before leaving the house and sprinkl Holy Water on their beds before retiring
Catholics before Vat II had fonts at each entrance to their homes and in each bedroom.
Catholic schools had fonts at the entrance of EACH CLASSROOM, and children blessed themselves entering and exiting the classroom every time.
When reaching for the Water a prayer is whispered, "By this Holy Water and Thy most Precious Blood wash away my sins O Lord, in the name of the Father etc"
Also, after blessing oneself with Holy Water, the excess on the fingers is flicked toward the ground/floor and one prayed, "for the Poor Souls in Purgatory"
Many saints have relayed that Holy Water is very beneficial for the Poor Souls, that's why we sprinkle it on graves when visiting the cemetery.
I watched an old black and white movie a couple months ago and the scene was a man entering a church and he did flick the excess Water on the floor.
Below are a couple excerpts from the Ecclesiastical Dictionary 1900 Pg 709.
"The use of holy water is an act of piety instituted by the Church, common among the Faithfull, and employed in all religious ceremonies. Holy water is used to drive away all that is evil and impure, and to draw down divine aid upon us, whether for the good of our soul or body."
""is beneficial to the bodies and souls of those who make use of it, and the banishment of what is foul and corrupt."
"We also know that holy water avails to procure the remission of sins, if those who employ it are rightly disposed. It is a customary practice to make the sign of the cross with holy water on entering or quitting a church; and at home in illness, temptation, or danger; a practice we should ever keep up in a spirit of faith and penitence, that we may derive, there from, all the salutary effect it meant to produce"
"The Church endeavors to address her children at the very threshold of the tabernacle, and to exhort them to understand, by the water which she holds out to them, that they must bring purity and cleanness of heart to the sanctuary"
Unfortunately, today we know more about what is happening in the world than we know about the customs of our faith.