WPA is a systematic method that is used to solve the water minimization problem in water and wastewater industry. However, this method is not friendly enough due to its tedious steps and procedures. This work aims to develop a graphical user-friendly interface by using VBA-Excel programming for synthesizing an optimal water network based on Water Pinch Analysis (WPA) involving a single contaminant. In this work, the available water network was first analyzed to identify water sources and demands. Then, limiting water data consist of flow rate and concentration values for demands and sources were extracted for the water data collection. A graphical user interface (GUI) for logging in, limiting water demand and source data, graphical, water network, and water integration systems also were developed. Next, the water targets were obtained by shifting the source composite curve and the water network was designed by implementing cleanest-to-cleanest rules. After inserting data into the interface, the results were generated automatically, resulting a minimum freshwater and wastewater flowrates. In an acrylonitrile production case study, two water demands consist of boiler feed water, and scrubber, and four water sources that includes distillation bottoms, off-gas condensate, aqueous, and ejector were identified. As a result, acrylonitrile production's wastewater reduction and freshwater saving were minimized by 38.32% and 70.61% respectively, by using VBA-Excel program. The result then has been validated and compared with mathematical programming technique. It was proven that graphical user interface that was developed in this work for synthesizing water networks based on WPA was found to be user-friendly and it can save the time requires to solve the water minimization problem. [ABSTRACT FROM AUTHOR]