The Pressure Dependent Demand is an option to address demand dynamics related to system pressure (i.e., impacts of system pressure on actual demand).
The Pressure Dependent Demand option in the Run Manger allows you to create a hydraulic model that more accurately reflects real-world conditions. In some water systems, as pressure drops, the ability to deliver the modeled demand also decreases with respect to a decrease in system pressure.
The Pressure Dependent Demand option is accessed from the Standard tab of the Run Manager. It is applied only on junctions within a domain that you defined. In other words, it is enabled only when a domain exists. You can then create and assign a curve of % Demand vs. Pressure to the current simulation.