Which information is typically recorded on a driller's log during drilling?

• A. Lithology notes
• B. Equipment serial numbers used
• C. Depth to groundwater
• D. Final analytical results

Answer: (C)

The main thing a driller tracks as the hole is advanced is where groundwater is first encountered. Recording the depth to groundwater provides a immediate, practical datum that guides how deep to drill before reaching the water-bearing interval, and it informs where to place the screen and casing. While noting lithology can happen, and other items like equipment serial numbers or lab results have their places, they’re not the information typically captured on a driller’s log during drilling. The depth to groundwater is the essential, routinely recorded datum that directly affects well design and future pumping considerations.