What Is Differential Pressure in Water Filtration?

Differential pressure is the difference between the pressure at the inlet of a filter and the pressure at the outlet. In water filtration, it is one of the most important indicators of filter condition. As debris builds up on the screen, water has a harder time passing through the filter, causing the inlet pressure to rise relative to the outlet pressure.

Why Differential Pressure Matters

• It indicates how dirty or restricted the filter screen is
• It can trigger automatic cleaning cycles
• It helps diagnose pressure loss and clogging problems
• It protects downstream equipment from reduced flow conditions

A properly sized filter should operate with an acceptable clean pressure drop and clean itself before differential pressure becomes excessive. If differential pressure rises too quickly or remains high after cleaning, the filter may be undersized, the screen may be too fine, or the water may contain more solids than expected.