Wetlands provide many services and commodities to humanity. Wetlands, the home of fish, animals, waterfowl and timber, provide important and valuable harvests and plenty of recreational fishing and hunting for local populations and tourists. At the ecosystem level, wetlands moderate the effects of floods, improve water quality and are aesthetically pleasing. They also contribute to the stability of the global levels of available nitrogen, atmospheric sulfur, carbon dioxide and methane. The hydrologic condition of wetlands is extremely important for their structure and functioning and affect many abiotic factors, including soil anaerobiosis and nutrient availability. In the following paper an evaluation of the hydrologic condition and quantification of the particular components entering into the water budget in the case of the Zelienka peat bog are presented.