Small diameter PVC (Polyvinyl Chloride) pipes are frequently used in irrigation systems for conveyance and distribution of water. In Japan, more than half of the existing 300 mm caliber pipelines are PVC. These pipes have the highest number of ruptures of all tube materials among Steel, Fiberglass Reinforced Plastic Mortar (FRPM), ductile, Prestressed Concrete (PC), asbestos and so on. Therefore, reducing the number of ruptures in PVC pipe is critical for keeping facilities secure and to reduce maintenance costs. This report discusses field research on ruptures in small diameter PVC pipes and the necessity of a water leakage detection technology. Crack surface analysis of PVC pipes revealed that fatigue fractures occur initially, followed by a gradual brittle fracture. A field study revealed that fatigue fractures may be caused by repeated loading due to water hammer pressure generated when there is a deflection in the inner material such as a distortion caused by an outside load. A monitoring facility is under development to detect cracks caused by fatigue fractures. This would be able to help discover signs of leakage and prevent brittle fractures.