From the core rule book, the spell "create water" includes the following:
Water can be created in an area as small as will actually contain the liquid, or in an area three times as large—possibly creating a downpour or filling many small receptacles.
This sounds like there might be an upper limit to the volume of the container in which you can create your water, but that seems like a strange arbitrary restriction. Is there actually an upper limit to the size of the container in which you can cast create water? If not, why are the words "or in an area three times as large" included?