Modern law is composed dominantly of new fields of complex legislations such as biotechnologies laws, environmental laws or intellectual property. But a particular legal area stigmatizes more than the others this increasing complexity: the water protection laws.Due to its origins deeply established in the European culture, but also due to ethical, political, economical and social issues, water protection laws appear to be the typical representation of links between risk and complexity. The European water protection law is deeply complex on two scales. First, on the European scale: this field is characterised by a growing normative proliferation for the last thirty years, which seems to follow public opinion. Second, tools used by the European Union are dedicated to be transposed in each member state. In this way, European rules are integrated in each state legal order. But in many cases, only one transposition text is not enough. For example in France, the ?nitrates? water directive n˚91/676 required sixteen transposition texts.This complexity involves several difficulties. The natural's requirements of legal security and economical efficiency necessitate the removal of all deflections that discredit the law and threaten social cohesion. However, the multiplication of sources and authors of the law created increasingly complex situations. For example, the judge must not only apply national legislation, he also has to combine it with the texts from the European Union, international regulations, or independent administrative authorities. Moreover, despite the increased number of standards, the quality of European waters has not improved significantly since thirty years.The proliferation, the instability and the complexity of normative rules concerning water has deep consequences on the legal system and the environment. This paper presents the approach proposed by the European Union laws on water, an essential natural resource. Thus, an analysis of its social impacts will be proposed. We conclude by an analysis of the capacity of European Union law to cope with legal and environmental risks.