An industrial RO plant purifies water through a multi-stage process that begins with pre-treatment to remove large particles, chlorine, and other impurities. The pre treated water is then pressurized and forced through a semi-premeable membrane in the core RO system, which blocks dissolved salts, minerals, and contaminants to produce purified water (premeate) and a reject stream. The final stage is post treatment, which may include UV sterilization or remineralization, followed by storage in a tank.