Which method is commonly used for drilling water supply wells?

The cable tool method is widely recognized for its effectiveness in drilling water supply wells, particularly in areas where the geological formations are harder, such as rocky or dense substratum areas. This method involves a heavy bit that is repeatedly raised and dropped, allowing it to penetrate the earth. The bits are often made from materials that can withstand high pressure and wear, making this method reliable for accessing groundwater.

The cable tool method is advantageous because it can reach significant depths and handle challenging geological conditions that other methods might struggle with. Furthermore, it does not require extensive use of water or drilling fluid during the process, minimizing environmental disturbance and making it suitable for sensitive areas.

Other methods like rotary drilling or auger drilling have their applications, but they can be less effective in harder rock formations or may involve the use of drilling fluids that can complicate the process or have environmental implications. Hydraulic fracturing, while popular for natural gas drilling, is not considered a standard method for water supply well drilling, as its primary purpose is to enhance flow in oil and gas wells rather than access groundwater directly.