Water supply in slum area has been one of the most complicated tasks owing to a complexity in land tenure and rapidly changes in geography, population growth, and the uncertainties in the parameters influencing the time series and also due to the non-availability of adequate supply. Recently, geographical information system (GIS) has become quite popular and widely applied in various fields. This paper demonstrates the use of GIS to water supply in urban slum area to help and improve their quality of life (QoL). In particular, use of GIS technology to build a water supply management model in slum area. At present, in Chittagong city there are no proper water supply networks to supply the water in slum area. To illustrate the applicability and capability of the GIS, the Chittagong city, Bangladesh, was used as a case study. It is envisaged that, the proposed system can save much time, cost, and minimize the mistakes in managing operation and maintenance systems for water distribution networks.