What is the most common use of a piezometer?

• A. Water quality sampling
• B. Measuring water level
• C. Determining soil density
• D. Injecting grout

Answer: (A)

Piezometers are used to measure the pressure in the pore water by watching how high the water rises in a small tube installed in the ground. That height directly tells you the hydraulic head at that location, which is essentially the groundwater level or pressure. Because tracking hydraulic head and how it changes over time is the primary purpose of these instruments—helping you understand groundwater flow, gradients, and aquifer behavior—the most common use is measuring water level. While you can collect groundwater samples with a piezometer for quality analysis, this is not its primary, everyday function. The other options—determining soil density or injecting grout—aren’t functions of a piezometer.