The River InVertebrate Prediction and Classification System (RIVPACS) marked a major advance in biomonitoring techniques, introducing the reference condition approach. Here the physical and geographical characteristics of the river are used to determine what taxa would be expected to be present if the site were not polluted. This reference condition approach was subsequently adopted in the Water Framework Directive (2000), far reaching European Union legislation governing the management of Europe’s water resources. Although RIVPACS pre-dated the Water Framework Directive, this directive has had a substantial influence on recent development. Checks, and subsequent modifications, had to be made to ensure that the RIVPACS bioassessment tool complied with the legal framework. Also, the directive marked a move from assessing the influence of a single pressure (usually organic pollution) to a more holistic approach based on ecological (not chemical) quality. Taxonomic groups other than macroinvertebrates are now included in assessments, e.g. macrophytes, with a strong emphasis on the level of confidence and precision provided. New indices are being developed using objective statistical techniques to assess a range of pressures on ecological quality (e.g. acidification, low-flow, hydromorphology, heavy metals). As the directive requires member states to develop Catchment Management Plans that are capable of delivering “Good” ecological status, techniques are being developed that can predict the consequences and cost-effectiveness of catchment management measures. There is now an unprecedented drive to develop the wide range of biomonitoring tools needed to predict and support the return of ecological integrity to European waters after decades of pollution.