Directive 2000/60/EC (Water Framework Directive) requires member states to implement the necessary measures to prevent deterioration of the status of all bodies of surface water and to prevent or limit the input of pollutants in groundwater. It is complemented in 2006 by a specific directive on groundwater
based on article 17 of the WFD.
The application of water legislation to geothermal energy differs between open or closed-loop system. Article 11 of the WFD gives member states the option to authorise the reinjection into the same aquifer of water used for geothermal purposes if it does not compromise the environmental objectives of the directive. National governments have the competency to decide as to whether reinjection of the geothermal fluids is required.