[Exxy]

-Simple suggestion in concept, simply add more locations (existing or not) you can draw water from with a bucket.

Prime examples (all can be found in Tannis): The small pond in the north-northeast spot, the well near the inn, the barrel near the same inn (which could be thought as something to collect rainwater) or even the rain itself (although this one may kill the server with lag, not sure - kind of a scary thought now that I think of it).

Adding On

-Maybe make a watering pump or some other tool you can place down that requires materials (that can be considered of near or equal value) which could give you so-and-so % chance for Pure Water.