Which type of well is generally more dependable and less prone to contamination?

Drilled wells are considered more dependable and less prone to contamination due to their construction and the techniques used to create them. They are typically constructed using drilling equipment that creates a deep borehole, allowing access to groundwater that is often located at greater depths—generally beneath layers of soil and rock that can serve as natural filtration barriers. This depth reduces the likelihood of surface contamination reaching the water supply.

Furthermore, drilled wells are often equipped with protective casing, which effectively prevents contaminants from entering the well. The installation procedures include sealing the top of the well with a cap or protective head to minimize risks of contamination from surface runoff, animal intrusion, and other potential pollutants.

In contrast, other well types, such as dug, bored, and driven wells, are less effective at providing the same level of protection. Dug wells often collect water from the shallow groundwater that can easily be contaminated by surface water and nearby activities, while bored and driven wells, although deeper than dug wells, may not have the same protective measures as drilled wells. These characteristics make drilled wells the preferable option for ensuring water quality and safety.