The thesis deals with the issue of Legionella control in an internal drinking water network in a hospital. It follows the entire process of recording and decision-making in establishing a system for the control of legionella. In the beginning, the basic information, e.g. the review of the current technics, is presented. The classical method of thermal disinfection is introduced, and later on compared to the modern automatic method. The case of installation and operation in the reference object is described as well. The analysis of public and internal plumbing system, including the identification of pipelines in the main old building of Golnik Hospital follows. Based on the findings of the analysis the costs of the current disinfection plan are calculated, and the comparison of the investment costs for the automatic thermal disinfection, which is made on the basis of a renovation proposal, is presented. The focus is also put on the guidelines that should be taken into consideration before making a decision about the system for the control of legionella in the hospital.