The New York Bay Area, San Francisco Bay Area, and Tokyo Bay Area have experienced rapid development and are recognized as first-class bay areas due to their robust economic and social growth. These regions have enacted a number of laws and regulations and implemented effective engineering measures to address water resources, water supply, flood control, and water ecological conservation. These measures aim to meet the increasing demands of water security while sustaining the rapid growth of bay area economies. In this article we analyze the current water security status of first-class bay areas, focusing on aspects such as water resources allocation, water conservation, flood control, and watershed management. We introduce the methods and successful experiences employed by these bay areas in overcoming resource constraints, coping with extreme weather events, and protecting ecological environment. Drawing on the characteristics of water resources in the Guangdong-Hong Kong-Macao Greater Bay Area, as well as the challenges faced in terms of water resource constraints, extreme weather, and ecological environment protection, we propose several recommendations to enhance water management in the bay area. These include promoting coordinated governance and management of water resources, strengthening the water resources allocation network, advancing research and application of new products and technologies for water-saving in agriculture and households, improving water transmission pipelines, implementing flood insurance systems, and enhancing water ecological environment management systems. These suggestions aim to provide valuable insights for ensuring water security and facilitating high-quality development in the Guangdong-Hong Kong-Macao Greater Bay Area.