In pump performance curves, what relationship is typically shown?

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Pump performance curves illustrate how a pump’s hydraulic capability changes with flow. The vertical axis shows head—the pressure the pump can develop, usually measured in feet or meters of water—and the horizontal axis shows capacity or discharge—the flow rate, such as gallons per minute or cubic meters per hour. The curve typically slopes downward, meaning as flow increases, the head the pump can deliver decreases due to system resistance and pump design. This relationship lets you find the operating point where the system’s head loss matches the pump’s head, and it helps in selecting the right pump and evaluating efficiency. Electrical properties (voltage and current) or water chemistry factors (temperature and pH) or disinfectant-related metrics (discharge and chlorine residual) are not depicted on pump curves.