Monitoring of Zn2+ion in water is very important as it is a vital cation in the human body excess of which can be fatal. ZnO nanorods grown over interdigitated Cu electrodes can be used as an efficient Zn2+ ion detector in presence of UV light. This paper reports the response of the ZnO nanorods based sensor to water samples containing different concentration of Zn2+ ions. Keywords : Sensor, ZnO nanorods, Zn2+ ions, interdigitated electrodes