With the nationalisation of the mines on 1 January 1864 by the Kingdom of Hanover, not only did mining rights now transfer to the state, but also the rights to water usage. So the Kingdom of Hanover also claimed the Water Regale, which was first legally defined in the Prussian Water Law (Preußisches Wassergesetz) of 1913 in sections 16 and 381. Following the absorption of the Kingdom of Hanover into the Kingdom of Prussia, the Royal Prussian Mining Inspectorate (Königlich-Preußische Bergbauinspektion) and, later, Preussag took over the operation of mines in the Upper Harz.