In our current Pathfinder campaign, my party is (probably) dealing with a Vampire; one of the vampire weaknesses is to take damage in "running water".
We have multiple Clerics and a Druid in the party (all 6th level), and Create Water is an Orison, which means each of us could Create 12 gallons of Water every 6 seconds. That's a lot of water! Could this be used to create "running water" sufficient for hurting a Vampire?
The description of the vampire reads, "Each round of immersion in running water inflicts damage on a vampire equal to one-third of its maximum hit points—a vampire reduced to 0 hit points in this manner is destroyed." Emphasis mine.
I'll admit 12 gallons per person per round is a lot, but immersing--that is, submerging or completely covering the vampire beneath running water--is going to take a lot more than a few castings of the spell create water. You and your meddling friends are going to have to engineer a Scooby-doo style trap with dams and such to make the water actually run for that to work.
The Pathfinder vampire is killed by running water probably as a baptism metaphor, but also probably to give low-level players a method of destroying an otherwise powerful undead by bull rushing it into a river and winning grapple checks. The spell create water--a 0th-level spell usable infinitely in Pathfinder--I'm almost certain isn't supposed to nor intended to kill again Count Dracula or Baron Blood.
I would personally rule against it. The traditional folklore regarding running water referred to established streams and brooks and had as much to do with the idea of thresholds as it did with the water. Creating a splash of water, even the substantial amount from Create Water or a Decanter of Endless water doesn't create an established channel the way that a running brook or river does.
