This paper presents an assessment of how the European Water Framework Directive (WFD) is stimulating change in water and wastewater management. The paper aims to provide an organisational innovation contribution towards understanding the processes by which policy and legislation stimulate change in water and wastewater systems. Results were produced by analysing interviews with environmental managers from all water and sewerage companies in England and Wales. Results show that integrated water supply approaches are emerging in response to the WFD, while wastewater approaches are not changing to the same extent. Reasons for this difference are located in a mix of factors including: economic regulation; conflicting national and EU regulations; uncertainty; lock-in to infrastructure; the way in which different WaSCs frame business problems and opportunities, and a lack of technological knowledge. Results are discussed against an international review of water sector change and against government reviews of the water sector economic regulator.