Fibrous structures with nanoscale diameters offer a multitude of fascinating features, such as excellent mechanical behavior and large surface area to volume ratio, malcingthem attractive for many applications. Their large surface area also gives them high functionalization ability. Among the many techniques available for generating nanofibers, electrospinning is rapidly emerging as a simple process in which careful control of operating conditions and polymer solution properties enables the production of highly porous structures of smooth non-woven nanofibers. Compared to traditional phase inversion techniques for membrane fabrication, electrospinning allows the formation of interconnected pores with uniform pore size and porosities exceeding 90%. As a result, electrospun membranes are increasingly being applied to many water purification applications such as membrane distillation and pretreatment of feed prior to reverse osmosis or nanofiltration processes by the removal of divalent metal ions, grease and other contaminants. Although the use of electrospinning for membrane fabrication has previously been reviewed, the rapid increase in developments over recent years has necessitated the need for a review on the preparation and application of electrospun nanofiber membranes as the barrier layer for water treatment, with emphasis on the reinforcement and post-treatment of electrospun polymer membranes. (C) 2014 Elsevier B.V. All rights reserved.