The time it takes for a well drilling company to drill for a water well will depend on the depth of the water, soil conditions as well as weather.
Most drills can be fully drilled within 1 day if the well doesn't have to be too deep but for deeper wells it can take 2 to 3 days and in rare cases can take 4 days for completion of the well.
You also have to factor in the time it takes for the well drilling company to setup their well drilling rig which should only an hour or two.