The fixed part of the tariff should not exceed 30% of the total. Different tariffs apply to different water quality grades (raw water, settled water, purified w'ater). Revenues that correspond to abstraction are transferred to the relevant authority (provinces and metropolitan cities in the case of river water use; or K-water in the case of dam water). Revenues generated in addition to w'ater abstraction costs are earmarked for the operation of multi-regional water supply systems.