Economic instruments, such as water tariffs or pollution charges, are an important complement to technical, regulatory, and institutional tools to achieve a sustainable and efficient management of wastewater. Economic instruments use market-based, mostly monetary, measures with the objective to raise revenue to help finance wastewater services, to provide incentives to use water efficiently and carefully, to provide disincentives for the anti-social release of polluted wastewater, to make the polluter pay for the environmental damage done, and to raise awareness on the environmental and societal costs of water use and wastewater discharge. The most common economic instruments used in wastewater management are the pricing of wastewater services and levying of charges for wastewater discharge into the Environment. In this lesson, different economic instruments used in wastewater management will be presented. Special emphasis will be given to the various tariff structures that are used to levy wastewater service fees. Tariffs determine the level of revenues that service providers receive from users. They are designed for different purposes, and often contain some elements to address poverty.