Unexpected water shortages are common, especially in densely populated areas and homes. Water supply is carried out from a reservoir located on the roof of the building. Apparently, there is no early warning system that allows monitoring of the water level in the tank at a critical level. This situation occurs when there is no one to monitor the water level. People face such problems when the need for water is greater and when there is a large crowd of people. This paper proposes a solution for a water monitoring system using a Global System for Mobile communication (GSM) network to avoid such manual control problems. In this prototype, a water level message will be sent to a person whose mobile phone is connected to the GSM network so that the water level in the tank can be monitored and known. The pumping system automatically switches off when the water reaches its maximum level.