Available water resources are increasingly limited, operation of different monitoring systems is indispensable regarding to get water quality and quantity data to further analyses. Another highlighted aspect is the use of water for different purposes. To determine the usability of the surface or groundwater, we need to collect information about physical, chemical and biological water quality parameters. Long-term monitoring systems can help us in many different water management questions: sustainable water management, water resource allocation, reuse potential. Frame of this recent study, environmental status of the Rákos Stream- focusing on water quality and quantity - have been analysed by in situ measurements. The monitored parameters were the following: water temperature, water flow, chlorophyll-a (Chl-a), phosphate (PO43-), ammonium (NH4+), nitrite (NO2-), nitrate (NO3-), pH value, conductivity, dissolved oxygen (DO).