Energy consumption is continuing to increase, especially the consumption of fossil fuels. It is important, therefore, to make use of our limited energy sources and reduce carbon dioxide emission. Some natural energy resources, such as solar power, have been well studied; however, they require complex systems and introduce energy fluctuations. On the other hand, demand side management (DSM) can also be studied from the consumer's point of view. One of the challenges associated with DSM is reducing the energy consumption of pumps in commercial buildings. Although water cycling systems have been well studied by large water departments, the knowledge is not generally used in most commercial facilities. Therefore, this study aims to control a water circulation pump to reduce energy consumption while maintaining water quality. This approach is applicable to buildings with pools or hot springs that are expensive to operate and maintain. Automation of water circulation systems has been well studied only by water departments. However, general water purification systems can be expensive and are highly complex. For these reasons, this paper constructs a low-cost automatic water management system to reduce management costs. An experiment was conducted to demonstrate an automatic water management system that will effectively cut water management costs using low-cost sensors. We also experimentally obtained some parameters to facilitate automatic water management. Finally, the experimental system was found to reduce electricity consumption by 8%/day and reduce the electric peak by 30%.