The functions and utility of emission and immission standards are discussed as instruments in the management of water quality. Especially the intrinsic a-priori trade-off associated with setting immission standards, the complexity of the cause-effect relationships and the variability of water quality are used as an argument to rely less heavily on such standards. It is argued that simulation, systems analysis, Habitat Suitability Criteria and plan effect matrices are tools that can be implemented and used more effectively.