在廣闊的自來水供水管網系統中，如何選擇適當的區域，進行汰換老舊漏管線等管網改善工程，以往皆由工程師憑個人經驗，參考自來水管線圖後，就著手規劃、設計、施工。工程竣工後，也缺乏客觀資料可以檢視投資效益。日本東京都為了有效推動防漏對策，規劃防漏調查區劃的理念，正可以運用在管網改善工程上。運用小區計量作業提昇售水率之研究，首先介紹相關都市自來水管線防漏對策，接著完整紀錄國內首次都會區小區計量規劃與執行。執行作業期間，由於閥類圖資未能適時更新、現場埋沒比率偏高及部分損壞，造成操作困難，更須消耗相當時日調整，方能建立完整封閉區塊，提出閥栓維護的重要性及建立區塊管理簿管理觀念。本研究再針對二個區塊分析，證實透過小區計量作業的執行，確實可以明確掌握影響售水率因素，並提出改善對策，進行管線抽換後，售水率明顯提升，投資效益分別達4.63倍及3.17倍。 How we choose the suitable area to update old and leaking water pipes in the extensive water supply system. It depended on water engineers’ experience formerly. Water engineers began to map out, design and construct water pipes when they had consulted just the pipe blueprint. It results in that there is no objective data to survey the investment benefit. There is a better method to apply improving water pipe system. It modified the prevented leakage strategy by Tokyo Water Department. Taipei Water Department mark out the investigative distinct for prevented leakage as same as Tokyo Water Department. The steps of studying on the improvement of water-sold percentage by regional water quantity measurement are: First at all, introduction about the prevented leakage strategy in city water pipe system. Secondary, make the whole record at the first execution of regional water quantity measurement in city. It takes a long time to build a whole closed water pipe system area because of disappearance of the control valves and the mistakes of the pipe blueprint. We figure out the importance to set up the regional management books to maintain the control valves in my research. We can know well the most important factor at influence the percentage of revenue water by the analysis that was aimed at two particular areas. The percentages of improvement at investment benefit are 463% and 317% after following the improvement policy by regional water quantity measurement strategy.