According to one aspect of the present invention, there is provided a desalination system comprising a plurality of elongated pressure vessels (PV). Each PV has a longitudinal axis, oriented such that the longitudinal axis thereof is of a vertical orientation. Each of the PVs is adapted to receive therein a plurality n of desalination membranes. The membranes located above the lowermost membrane within the PV have a total weight allowing them to function as a mechanism limiting axial expansion of the lowermost membrane, whereby the PV is free of any additional limiting mechanism.
