1 ground (shallow watertable preferable)
as the whole becomes deeper you will need the bucket to remove the unwanted earth, you will also need to line the walls of the well with stones or bricks (to support the structure)
when you reach the watertable you have dug a well, you will know you have reached the watertable because the floor will get wet and you will not be able to continue digging.
-the water may appear dirty, it is actually muddy. The mud filters the water removing all of the dirt.