The Bundeskartellamt is carrying out extensive investigations into urban water supply and has requested data from every city in Germany with a population of more than 200,000 since 2010. In May 2012, Stadtwerke Mainz undertook to reduce its water prices (excluding taxes and duties) by approximately 15% with effect from 1 January 2013 in a binding commitment decision. In June 2012, the Bundeskartellamt issued its final decision against Berliner Wasserbetriebe ordering the utility to lower its excessive drinking water prices. In its decision the Bundeskartellamt ordered that the utility’s revenue (excluding taxes and duties) from the supply of drinking water in Berlin must be reduced by 18% for 2012 and by 17% on average for the period 2013-2015.