Which device measures flow in an irrigation zone?

• A. A moisture meter
• B. A rain gauge
• C. A pressure gauge
• D. A flow meter

Answer: (D)

Measuring flow in an irrigation zone is about quantifying how much water passes through that zone per unit of time. A flow meter does exactly that by measuring the volumetric flow rate, usually in units like gallons per minute or liters per second, and often can totalize the amount of water over a period. This direct measurement lets you confirm that the zone is receiving the intended amount of water and helps you spot issues such as leaks, undersized piping, or misconfigurations in valve sequencing.

A moisture meter, by contrast, checks how much water is in the soil, not how much is moving through the system. A rain gauge records the amount of precipitation that falls on the area, not the irrigation flow. A pressure gauge shows the pressure in the line, which relates to flow indirectly but does not measure the actual flow rate. So the device that measures flow directly is the flow meter.