Chlorine, similarly to other elements, undergoes a complex biogeochemical cycle that includes the formation, conversion, and degradation of different inorganic and organic forms of chlorine. Chlorinated compounds participate in natural processes, biological, and chemical processes forming volatile organochlorine compounds; human activities also change their presence in the environment. Chlorinated pollutants are in the center of interest due to their reactive nature, causing degradation of ozone in the atmosphere, and due to health concerns, as some chlorinated compounds are highly toxic. Some volatile chlorinated hydrocarbons (VCHs) are both reactive and toxic, such as chloroform. Moreover, chloroform has natural and anthropogenic sources and can be formed in abiotic and biotic processes. In this chapter, we discuss the role of VCHs in the natural environment and their anthropogenic impact. Furthermore, statutorily determinations of adsorbable organic halogens (AOX) and chloroform will be evaluated in connection with a sample study in a clean area Hamry, Czech Republic. The catchment has low human activity and the collected water in the Hamry water reservoir is used as a source of drinking water. The area contains many bogs and forests and a high content of dissolved organic carbon has therefore been determined in it. The high concentration of AOX and chloroform in the water source area is caused by the natural biological activity of the soil. The compounds cannot be found in the reservoir, as the AOX are diluted, while chloroform is evaporated during on their course to the reservoir.