A catholic supply store
I don't believe that you need to PURCHASE Holy Water. Just go a Catholic church and ask Father to BLESS the water that you bring in a proper vessel. You may give a donation if you want which would be a nice thing to do. I believe that is correct. You may also call a Catholic Church to be on the safe side. Whatever bring a jar or something to carry the BLESSED WATER. ✝️
You don't purchase it's free. Any Catholic Church has it. Just ask & bring something to fill.
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