The interplay of water resources with economic and social spheres involves a reciprocal feedback mechanism. Investigating the adaptation status of the composite system consisting of the two is crucial for promoting sustainable and coordinated development. Based on the current situation in water resources and economic-social development in Hunan Province, China, a evaluation system with 22 indicators was established. The quantitative analyses were conducted using improved coupling coordination models, harmonious development models, and OECD models to assess the adaptability of 14 cities (prefectures) in Hunan Province. The results indicated the following: 1) Recently, water resources subsystems (WRS) development index in various cities (prefectures) in Hunan Province has shown signs of improvement, while the economic-social subsystems (SES) development index has exhibited a palpable upward trend. 2) Currently, the coupling coordinative degree between the two subsystems has reached a state of coupling coordination, but spatial differences between north and south regions still existed. 3) The lagging development trend in Hunan Province indicates that the growth rate of WRS has surpassed that of SES. However, the harmonious development capacity of the composite "Water-Economy-Society" system remains relatively low, whilst the contradiction between economic-social development and water resource scarcity has not been effectively alleviated.