D.Ing. / This thesis considers water supply and divides the water supply environment into three categories; the macro water supply environment, the water supply scheme and the consumers. Each of the categories is briefly explored in terms of the factors that may influence it. Subsequently, some of the unique features of a bulk water distribution system are dealt with, as well as different approaches related to bulk water distribution system design and assessment. One of these approaches, the probabilistic approach, offers unique features to assess the reliability of a bulk water distribution system but requires that the probabilistic characteristics of the stochastic events be quantified. The above prompted the goal of this thesis; “…to assess and quantify the probabilistic characteristics of selected factors that may compromise bulk water distribution reliability”. The objectives set and dealt with in this thesis are: • Conducting a literature review that explores uncertainty, reliability, models and techniques, highlighting selected factors that may compromise bulk water distribution reliability, as well as bulk water distribution system water requirements. • Quantifying the probabilistic characteristics of water distribution pipeline failures. • Quantifying the probabilistic characteristics of pipeline failures caused by sinkholes in dolomitic areas. • Quantifying the probabilistic characteristics of power supply failures. This study provides a comprehensive summary of a range of uncertainties that may compromise bulk water distribution reliability. However, the greatest value added corresponds to the following: • It establishes a benchmark related to the probabilistic characteristics of pipeline failures for five pipeline material categories, related to pipeline failure rates and pipeline repair times. • A new methodology is developed in terms of which the probabilistic characteristics of pipeline failures caused by sinkholes in dolomitic areas can be quantified. • It provides a benchmark of the probabilistic characteristics of power supply failures at bulk water distribution pump stations. Proposals are made related to future research needs, divided into two categories: • Complementary research needs that will complement and enhance the work undertaken within this thesis. • Promotional research needs that will promote the practical application of the outcomes generated as part of this thesis.