According to the Water Resources Act (WHG), depots must be equipped with fire water retention to retain contaminated extinguishing water or water-polluting substances. The affected systems include e.g. forwarding agencies, waste disposal companies, biogas plants, factory premises and depots with transhipment points and filling areas. The transfer shafts must be equipped with safety slides so that the water-polluting substances cannot get into the public sewage system or the municipal sewage treatment plant.