How is water supply verified when pumping from a hydrant or relay operation?

• A. Rely on experience alone.
• B. Check only the discharge pressure.
• C. Check only the inlet pressure.
• D. Monitor pump discharge pressure, inlet/outlet pressures, and ensure adequate water flow.

Answer: (D)

Verifying water supply while pumping from a hydrant or in a relay relies on real-time measurements of what the pump is doing and what the source is providing. You need to monitor pump discharge pressure to know what the system is delivering, check the inlet (suction) pressure to ensure the pump remains primed and the source is supplying water, and confirm there is adequate water flow through the lines. This combination ensures the pump isn’t starving for water or over-pressurizing against a restriction, and that the scene demand can actually be met. Relying on experience alone or only looking at a single parameter can hide problems—low suction might starve the pump, while high discharge with poor flow could indicate a restriction or insufficient supply. If any pressure or flow indicators indicate a problem, you adjust the setup to maintain safe suction and sufficient flow to the attack lines.