The depth of an agricultural well depends on its intended use. In areas with sandy soils, you may only need a shallow well that reaches groundwater levels at 30 feet or less. If your soil is rocky and hard to penetrate, you will want to drill a deeper well to access groundwater at greater depth without encountering as many obstacles.
Before beginning construction, you should know how deep agricultural wells are in your area. You can find this information by talking with local farmers or searching online resources such as county extension offices or local government websites.