This important book provides a comprehensive account of the role of the law concerning impacts on the aquatic environment and the realisation and maintenance of environmental objectives for different kinds of waters. The full range of criminal, civil, administrative, European Community and international law that bears upon protecting and improving water quality is examined and placed in perspective alongside the underlying environmental problems, the principal activities that are regulated and the range of potential legal strategies by which they may be addressed. Alongside detailed coverage of established topics such as the role of private law and criminal law in responding to water pollution incidents, particular emphasis is given to a range of recent developments of profound theoretical and practical importance. The book is written equally for legal practitioners, readers concerned with the wider debates on environmental regulatory strategy and the wide range of 'environmental practitioners' engaged in advising on water quality issues or campaigning for improvements.