The Create Water spells reads:
In an open container, you can create up to 10 gallons of drinkable water. You may also produce a rain that falls within a 30-foot cube and extinguishes open-air flames.
Must the container be filled by the water created? IE, a horse trough or sinkhole would not be valid targets, since they can hold more than 10 gallons of water?
If not; what prevents me from simply choosing the room I'm in as the container? For example, creating 10 gallons worth of water on the floor with the intent of freezing it to make ice terrain?
Or further, choosing the room and creating a gush of water over an unruly bar patron to "cool them off" - I can create rain, does something restrict me to Creating Water on or very close to a surface?