本文以教育部補助設置雨水回收完工滿一年以上共62 校次之永續校園為對象，得有效樣本23 例。82％學校肯定雨水貯留再利用系統，85％學校特別製作專屬教案，以落實基層教育。在回收效益方面，每千元之工程投資經費，平均每年能回收水量2.43M3。在設備維護費方面，平均每年僅佔初期投資工程費之0.26％。在經濟效益方面，平均回收年限為19年。在貯留系統設計方面，多數樣本在廣闢回收水源、加大集雨面積、貯槽容量等方面，仍有改進空間。本文針對雨水回收系統，以年雨量、集雨面積、貯槽容量及工程經費等變數，分別建立貯留系統之年回收水量及投資報酬效益的複迴歸預估模型，其重相關系數分別達.843 及.820。期本文能供設計者或使用者考量設備、設施或使用條件時之參酌，亦能為缺水的台灣、人均日用水超高的台灣，謀求一線解決的生機。 This research is intended to investigate the validity and economic efficiency of samll-scale rain water reuse system. The subjects are 62 sustainable schools subsidized by Ministry of Education for more than one year, and total 23 of them become valid samples. On the whole, 82％ of the schools confirm the reuse system of rain water system. 85％ of the schools had the specialized teaching program based on water resources reuse system to carry out the basic education. As for the rain water reuse efficiency, average annual reuse amount is 2.43M3 per thousand NTD construction cost. In terms of the maintenance cost, the average annual cost of rain water use is 0.26％ of the initial construction cost. In terms of economic efficiency, the cases of rain water reuse can regain the investment within 19 years. In terms of system design, most subjects need to improve in many perspectives, such as widening recycled water, enlarging catchment area and containers. In the end of the research, 2 multiple regression equations were set between reuse water quantity and investment reward efficiency in terms of annual rainfall, catchment area, container quantity and construction cost. The R2 is 0.843 and 0.820. It is hoped that this research can provide equipment and installation references of rain water harvesting system to designers. The reuse of rain water is one of the key strategies in dealing with the water shortage in Taiwan.