2. What exactly is water pressure and how is it measured?
Imagine the water contained in the system in the form of a column; the “weight” exerted by the column on its base is the pressure.
Measured in BAR, pressure is defined "static" when the system is closed, "dynamic" when it is operating. Dynamic pressure is always lower than static pressure, because of the flow resistance caused by surface friction inside the water hose: the narrower and longer the hose, the greater the flow resistance.
You should know the dynamic pressure of your water system, as it should be sufficient to ensure proper operation of watering devices. Refer to the table in the Claber guide to calculate your water pressure, quickly and easily.
