Quality of Near-surface Groundwater
The city of Berlin draws its drinking water entirely from its own resources. The quality of the groundwater beneath the city plays a pivotal role in this. The purity of Berlin’s groundwater has been directly and indirectly influenced by its inhabitants for a very long time. The air quality and the quality of precipitation, which is influenced by the former, as well as the volume of rain play an important role here. Vegetation and soils serve as initial natural layers that rainwater filters through before eventually recharging the rainwater, which may take up to many years and even decades.
So, how much rainwater seeps into the ground and where? How long before it reaches the groundwater and in what condition does it arrive? Which ice-age sediments or rock layers does it traverse or filter through on the way? Which chemical substances are released or absorbed or transformed by microbes? Even in Berlin, a large variety of geographic, geological and hydrogeological factors play a crucial role, whether we are looking at Kollwitzplatz or the Tempelhofer Feld, the Tiergarten or the Grunewald, the Müggelberge or the Spandauer Forst. Every location and its history influence the chemical and physical properties of groundwater sometimes following characteristic patterns.
The key issue, technically and scientifically, is the impossibility of descending into the groundwater to take measurements in Pankow or Marzahn. Recording and evaluating the quality and the properties of the groundwater is therefore a complex endeavour. For this purpose, the Berlin Senate Department has maintained an extensive state measuring network for decades. Every six months, groundwater samples are extracted from more than 200 measuring points at depths of up to 300 metres and are then chemically and physically analysed at the state laboratory. A wide range of natural components including calcium and sodium, but also heavy metals such as arsenic and cadmium, pesticides and drug residues, as well as nutrients, including phosphate and nitrate, are investigated. Within the drinking water protection zones, the Berlin Waterworks (BWB) maintain their own additional monitoring network with the purpose of identifying risks regarding drinking water production facilities early and of taking counteraction together with the Senate Department.
The quality of our groundwater and drinking water is assessed and the results are published in accordance with European and national law and regulations. To this end, the Senate Department for the Environment, Urban Mobility, Consumer Protection and Climate Action is in regular exchange with colleagues from other Berlin institutions, state and federal authorities, such as the Federal Environment Agency (UBA), as well as a wide range of research institutes and universities.
Berlin has a long-standing tradition of monitoring its groundwater. Following World War II, the measuring networks of the city developed independently of each other. They were able to join forces only after German reunification. From 1990, the results could therefore be extrapolated to the total area of the city once again. Find out all about the quality of groundwater prior to the year 2000 here.