Under the item description for Holy Water, we see the following:
A cleric or paladin may create holy water by performing a special ritual. The ritual takes 1 hour to perform, uses 25 gp worth of powdered silver, and requires the caster to expend a 1st-level spell slot.
This very closely matches one of the uses of the Ceremony spell:
1 hour (Ritual)
Components V S M (25gp of powdered silver; consumed)
Bless Water: You touch one vial of water and cause it to become holy water.
Do clerics and paladins actually need to have access to the Ceremony spell in order to bless water into Holy Water, or can they always do it (provided that they have the five pounds of silver powder, 60 minutes, and 1st level spell slot)?