In the 2015 River Weser case the Court of Justice of the European Union (CJEU) appears to demand a rather strict one-dimensional protection of water quality under the EU Water Framework Directive (WFD). Article 4 WFD, the very essence of this EU directive, should then be read as a strict water quality assessment on good ecological potential and other ecological WFD criteria. This jurisprudence could surely be welcomed as it secures blue environmental interests, but it may at the same time easily be encountered and criticized as a contradiction of modern EU policy documents on sustainable development and green or blue growth, as it may de iure subordinate socio-economic interests. It also may exclude clusters of ecosystem services; not only provisioning and cultural services, but also other not legally protected regulating services. Here, a CJEU-induced limited testing on only a few limited ecological criteria of Article 4 WFD might tend to resemble the one-criterion testing of the Natura 2000 habitats assessment and its possible shortcomings in terms of sustainable multi-functionality. In the derogation regimes of both WFD and Habitats Directive only overriding public interests may outweigh environmental objectives. In a recent 2016 case on hydropower the CJEU makes it clear renewable energy production can be such an overriding public interest, but still not all interests or ecosystem services do qualify to be part of a weighing process in the derogation stage. We should be aware this may contrast with current EU environmental policy documents like Green Infrastructure and Blue Growth. It would help if EU policy documents could be more explicit that sustainable development might be the default throughout Europe, but not necessarily in WFD waters and Natura 2000 sites.