A hyperfiltration system (10) and method for treating water including: a vessel (20) having a feed inlet (22), a permeate outlet (24), and a concentrate outlet (26); at least one spiral wound membrane element (28) located within the vessel (20); a pump (30) having a low pressure side (32) in fluid communication with a source of feed water (40) through a junction point (42) and a high pressure side (34) in fluid communication with the feed inlet (22); a permeate valve (50) connected to the permeate outlet (24) and adapted to selectively direct permeate flow between a treated water outlet (52) and the junction point (42); a flow path (60) between the concentrate outlet (26) and a discharge (62); and a flow restrictor (64) located along the flow path (60) and adapted to vary resistance to concentrate flow between a high and low value.