The importance of water for health and livelihood of the people is priceless, so its pollution constitutes a growing problem. Since natural drinking water is irreplaceable and invaluable public good, handling with sources of drinking water and its supply is very strictly regulated by the European and Slovenian regulations. The regulations of drinking water are exactly provided by the regulation Pravilnik o pitni vodi. It also commits the operators on drinking water supply to the internal control of drinking water by the principles of the HACCP system. HACCP is an internationally established preventive system for ensuring food safety that specifies control methods and recognizes the critical control points. The materials in contact with drinking water pose a potential health risk to the wholesome drinking water and thus indirectly also to human health, because their decomposition processes may lead to the migration between the material and the water. Although the first polymeric materials were produced at the end of the 19th century, we still place them amongst newer materials. Thus recently, these materials are increasingly being used in water supply systems. Despite the fact that their use has a number of advantages, their use also has some disadvantages. It is crucial to consider which materials will be selected and installed during facility design and construction, what are their characteristics and potential impacts on the wholesome drinking water. The thesis presents the polymeric materials that are commonly used in the water supply systems, their chemical composition, properties and intention of use. This also includes additives and fillers which have been added, their influence on the properties of polymers and polymer material impact on the wholesome drinking water. The subjects of interest are also the ways and methods of testing these materials. The results and conclusions are presented by a SWOT analysis that reveals the main advantages and disadvantages of the polymeric materials usage in water distribution systems. The SWOT analysis also offers new opportunities for improvements and additionally draws attention to the problems that may occur. Finally, we have made a study of the actual situation of the installed materials in the System in Pomurje – C system.