A spiral wound membrane module including a specialized endcap assembly including a connecting conduit defining a passageway extending radially inward from its outer periphery, and a differential pressure sensor connected to the passageway of the connecting conduit.

A spiral-wound module as a type of a membrane is made of at least a metallic, hollow cylindrical permeate tube, a two-dimensional rectangular membrane wound in a spiral wound around the permeate tube, two axial stops fitted to the permeate tube on either side of the spiral winding and a metallic, hollow cylindrical outer tube extending the outer limits of the permeate tube.