How can you verify that a hydrant is delivering the expected flow?

• A. Observe discharge pressure on the discharge gauge, compare to hydrant test data, and measure actual flow with a flow meter or friction loss calculation.
• B. Only check the color of water.
• C. Ignore readings and rely on feel.
• D. Ask the driver.

Answer: (C)

To verify hydrant flow, use objective hydraulic measurements rather than subjective cues. Check the discharge pressure with the hydrant’s gauge and compare that reading to the established hydrant test data for that site. Then determine the actual discharge flow either with a calibrated flow meter on the hydrant or by calculating it from the measured pressure drop using a friction loss method (and the known pipe length, diameter, roughness, etc.). When the measured flow and pressure align with the test data, you can be confident the hydrant is delivering the expected flow. If there’s a discrepancy, investigate possible causes such as blockages, valve position, or upstream supply issues. Relying on color, feel, or non-instrument cues cannot reliably quantify flow.