There is a growing tendency in the application of the quality management system to the construction industry. Within this perspective, some quality management standards, like ISO 9001, are utilized to assure the quality in projects. Application of this system to water resources projects is also of importance since they are very large systems having various components for which quality management would improve the overall efficiency. The aim of this thesis is to examine the implementation of the quality management in the design and construction processes of a sample irrigation network in order to evaluate its benefits by the cost of quality, which is assumed to be the most effective performance measure. To this end, the prevention and appraisal costs and failure costs, which constitute the cost of quality,are identified separately and their interactions are investigated on a case study in which the causes of these failures are analyzed and quantified in the form of graphs.