Membrane housing is a pressure vessel for loading membrane elements in a reverse osmosis water treatment system. Currently, there are three types of membrane housings with different materials for water treatment on the market: FRP (fiberglass reinforce plastic), stainless steel and PVC.

Most commonly used RO membranes are typically composed by a thin film composite membrane consisting of three layers: a polyester support web, a microporous polysulfone interlayer and an ultra think polyamide barrier layer on the top surface.