In which unit is water pressure typically measured?

Water pressure is typically measured in PSI, which stands for pounds per square inch. This unit quantifies the force exerted by the water against a surface area of one square inch. PSI is widely used in various applications related to water distribution and plumbing because it provides a clear understanding of the pressure within pipes, pumps, and systems.

Other units provided in the choices do not measure pressure directly. Gallons per minute relates to flow rate, indicating how much water flows over time. Liters also measure volume, not pressure. Feet of head can be used to represent pressure in some contexts, especially in hydraulics, but it essentially translates the pressure into the height of a column of water rather than a direct pressure measurement in pounds per square inch. Thus, PSI is the standard unit for measuring water pressure, making it the correct answer.