"The episcopal blessing, the aspersion of holy water, every sacramental unction, prayer in a dedicated church, and the like, effect the remission of venial sins, implicitly or explicitly" (Summa III, Q. lxxxvii, a. 3, ad 1um).
Is Lourdes or Walsingham water holy water?
The answer is NO.
Only water blessed by a Catholic priest is holy water, which is a sacramental and gives a partial indulgence.
Sacramentals help us daily, and remit venial sin, but only as ordered by the Church. Sacramentals can also drive away demons, as holy water, for example, is exorcised by the priest and added with exorcised salt. But, it is forbidden for the laity to exorcise or cast out demons with holy water in any sort of prayer without being with a priest who is an exorcist and unless those lay people are appointed by a bishop as part of an exorcist team. The holy water keeps demons away and my parents, for example, had holy water fonts in each child's bedroom on the wall.
Mary is not a priest. Priests have powers Mary does not have, like changing the bread and wine into the Body and Blood of Christ or forgiving sins and granting absolution. She gave us the Bread from Heaven in the Child Christ, but Christ instituted the Eucharist and Confession and all the sacraments for the priesthood alone.
Sometimes Catholics and Anglicans do not understand Mary's role in the Church. She is the Mother of God, not a priest. She cannot bless water to make it holy. The priest is the Alter Christus, the Other Christ.
Mary cannot and does not bless water. Her water at Lourdes, and some say there is Fatima water, is not holy water, not sacramental.
Lourdes water was given for healing purposes only and is her gift for healing. This water is not a sacramental, which like all sacramentals, comes under the jurisdiction of the Vatican, through the Pope, to the bishops and priests.
In cases of emergency, ordinary water may be used for baptism and if you have Lourdes water around, that would be ordinary water not holy water.
|Thanks to Wiki for photo|
The wells at Walsingham, according to my research of old sources, were dug by Richeldis' son for the use of the pilgrims. The springs were already there and people knew about them. Even if Mary has something to do with the waters, which I cannot determine by sources, it still would not be holy.
Therefore, there is nothing holy about the water in the Anglican Shrine in Walsingham and remember, Anglican priests do not have Holy Orders and therefore, the water is not blessed if they bless it. They have no more power to bless water than I do. Pray for Walsingham, as there is much confusion there.
I add the rite for the blessing of holy water from
1. RITE FOR PROVIDING HOLY WATER
Some minor changes have been made in this rite, such as the omission of certain words, putting salt into the water only once, and the use of the short conclusion for the orations (see "Ephemerides Liturgicae" 75  426). The holy-water font is a counterpart of the baptismal font; and the sacramental use of holy water is related to the great sacrament of water, baptism. Easter is the day par excellence for baptism, and every Sunday is a little Easter. Consequently, on the Lord's day the Church blesses water to be used in the ceremony of renewal of baptism, for as often as she sprinkles us with the blessed water a sign is given us of that sacrament which once bestowed the gift of life. The rubrics direct that the water may be blessed either in the church proper or in the sacristy. For the edification of the people it might be well to perform this blessing in the sight of the people, at least occasionally. The practice of putting salt into the water comes no doubt from the incident of the miraculous cure of the poisonous well (see 4 Kings 2.19-21), where the prophet Eliseus used salt to purify the water of the well.
1. On Sundays, or whenever this blessing takes place, salt and fresh water are prepared in the church or in the sacristy. The priest, vested in surplice and purple stole, says:
P: Our help is in the name of the Lord.
All: Who made heaven and earth.
2. The exorcism of salt follows: God's creature, salt, I cast out the demon from you by the living God, by the true God, by the holy God, by God who ordered you to be thrown into the water- spring by Eliseus to heal it of its barrenness. May you be a purified salt, a means of health for those who believe, a medicine for body and soul for all who make use of you. May all evil fancies of the foul fiend, his malice and cunning, be driven afar from the place where you are sprinkled. And let every unclean spirit be repulsed by Him who is coming to judge both the living and the dead and the world by fire.All: Amen.
Let us pray.
Almighty everlasting God, we humbly appeal to your mercy and goodness to graciously bless this creature, salt, which you have given for mankind's use. May all who use it find in it a remedy for body and mind. And may everything that it touches or sprinkles be freed from uncleanness and any influence of the evil spirit; through Christ our Lord.All: Amen.
Exorcism of the water:
God's creature, water, I cast out the demon from you in the name of God the Father almighty, in the name of Jesus Christ, His Son, our Lord, and in the power of the Holy Spirit. May you be a purified water, empowered to drive afar all power of the enemy, in fact, to root out and banish the enemy himself, along with his fallen angels. We ask this through the power of our Lord Jesus Christ, who is coming to judge both the living and the dead and the world by fire.All: Amen.
Let us pray.
O God, who for man's welfare established the most wonderful mysteries in the substance of water, hearken to our prayer, and pour forth your blessing on this element now being prepared with various purifying rites. May this creature of yours, when used in your mysteries and endowed with your grace, serve to cast out demons and to banish disease. May everything that this water sprinkles in the homes and gatherings of the faithful be delivered from all that is unclean and hurtful; let no breath of contagion hover there, no taint of corruption; let all the wiles of the lurking enemy come to nothing. By the sprinkling of this water may everything opposed to the safety and peace of the occupants of these homes be banished, so that in calling on your holy name they may know the well-being they desire, and be protected from every peril; through Christ our Lord.All: Amen.
3. Now the priest pours the salt into the water in the form of a cross, saying:
May this salt and water be mixed together; in the name of the Father, and of the Son, and of the Holy Spirit.All: Amen.
P: The Lord be with you.
All: May He also be with you.Let us pray.
God, source of irresistible might and king of an invincible realm, the ever-glorious conqueror; who restrain the force of the adversary, silencing the uproar of his rage, and valiantly subduing his wickedness; in awe and humility we beg you, Lord, to regard with favor this creature thing of salt and water, to let the light of your kindness shine upon it, and to hallow it with the dew of your mercy; so that wherever it is sprinkled and your holy name is invoked, every assault of the unclean spirit may be baffled, and all dread of the serpent's venom be cast out. To us who entreat your mercy grant that the Holy Spirit may be with us wherever we may be; through Christ our Lord. All: Amen.
4. On Sundays after the water is blessed and before Mass begins the celebrant sprinkles the altar, himself, the ministers, and the people as prescribed in the Missal and in the ceremony of the Ritual given below.
5. Christ's faithful are permitted to take holy water home with them to sprinkle the sick, their homes, fields, vineyards, and the like. It is recommended too that they put it in fonts in the various rooms, so that they may use it to bless themselves daily and frequently.
For a discussion on the new and old rites of holy water, see Fr. Z's blog here.