This work covers the topic of metals and semimetals in water. It is divided into three parts. First, each element is characterized by its properties and behavior in water. Incidence in the environment, utilization and effects of intake on human body are described for each element. Second, means of elimination from water are introduced. Different chemical, mechanical and biological methods are discussed. In greater detail, precipitate method, cementation, electrochemical processes, sorption and biosorption are reviewed. Third, hands-on filtration experiment of polluted water with the help of different filtration materials is included. This experiment was done in a laboratory belonging to the Institute of Municipal Water Management, Faculty of Civil Engineering, Brno University of Technology.