This study aimed at defining approaches to develop a planning system for water management at the province level in Nakhon Pathom Province. The methodology included review of previous study reports, interview, and field survey. From the obtained information, it was revealed that data for water management planning at the province level were still limited. Having been supplied water from the Greater Mae Klong Irrigation Project, Nakhon Pathom Province expressed less water deficit problem. However, severe flooding problems were reported in both banks of Tha Chin River. The planning system for water management, being developed in the next research step, ought to provide information related to conditions of water. Moreover, at the local level, the system should be capable to present information about water quality and waterrelated infrastructures. The latter task would be accomplished in pilot areas with community participation.