WATER TREATMENT SYSTEM

PROBLEM TO BE SOLVED: To provide a water treatment system which can easily control recovery rates of pressure containers at the same level.SOLUTION: A water treatment system includes: a membrane module 22 for filtration of water; a pressure container 21 which accommodates the membrane module 22; permeate piping 23 which discharges a permeate obtained by the filtration in the membrane module 22; supply water piping 21h which is provided with a plurality of pressure containers 21 each accommodating the membrane module 22 and connects the pressure containers 21 in parallel so that supply water to be filtered is supplied to the membrane modules 22 respectively accommodated in the plurality of pressure containers 21; and flow control means 25 which is provided in the permeate piping 23 and controls the flow rate of the permeate flowing through the permeate piping 23 based on the ion concentration in the remainder of the supply water, discharged without filtration, in the supply water supplied to the pressure container 21.