Policy responses to address agricultural water pollution across OECD countries have typically used a mix of economic incentives, environmental regulations and information instruments. A large range of measures have been deployed at the local, catchment, through to national and transborder scales, across an array of different government agencies. Many measures to control water pollution from agriculture are voluntary. Water supply utilities and the agro-food chain are also engaged in co-operative arrangements with farmers to minimise pollution, such as providing farm advisory services. This policy mix has had mixed results in lowering agricultural pressure on water systems. Over many years these policies, according to OECD estimates, have cost taxpayers billions of dollars annually. For some countries policies to reduce agricultural water pollution have been successful, with a package of input taxes, payments and farm advice. In other cases, despite substantial expenditure on efforts to lower agricultural pollution of a specific water ecosystem, little progress has been made. More recently, some private and public initiatives, for example, water quality trading in agriculture and establishing co-operative agreements to address water pollution are showing signs of success, albeit on a limited scale to date.