The pressure in a system when no water is flowing is called ________ pressure.

The term that describes the pressure in a system when no water is flowing is static pressure. Static pressure reflects the potential energy stored within the fluid, providing insight into how much pressure is present without the influence of movement. This measurement is crucial in various applications, such as firefighting systems, where understanding the pressure when the system is idle allows for the proper design and assessment of water supply, distribution, and system efficiency.

Dynamic pressure, on the other hand, refers to the pressure when fluid is in motion and can indicate flow characteristics. Positive pressure typically means that the pressure is above atmospheric levels, and negative pressure would suggest a vacuum or pressure below atmospheric levels. Neither of these concepts applies to the scenario described, where the fluid is stagnant and thus not contributing to dynamic pressure measurements.