Water is the first resource you're taught to gather in Castleville Legends. I have to admit, I got a little excited when I first gathered water; as an original Castleville player, the process was so much simpler!
Basically, water is the one and only free resource in the game, and you can seemingly collect and store as much of it as you want (at least, I've never hit a limit. You collect it by tapping on any pond and river, and this collects four waters at a time.
Water is used to grow many of the other resources, and it takes one watering to create one batch (however large that may be) of each resource.
Below is a list of resources fed by water; simply click on the name of a resource to learn more about it, including how many of that resource is produced by each watering.
Bed of Lavender
Purple Spangle Herb
Ice Bell Flower