For discharges into surface waters the WFD applies a ‘combined approach’ by providing for limitations on pollutant releases at the source, as well as the establishment of EQS. To this end the Member States were required, at the latest by 2012 unless otherwise specified, to establish and/or implement the emission controls based on BAT, or the relevant emission limit values as set out in any relevant EU legislation, 
including what is now the IED (Directive 2010/75/EU) and the Directives listed in Annex IX of the WFD. In the case of diffuse impacts, controls—including, as appropriate, best environmental practices—were to be implemented. However, these obligations are linked to EQS through a requirement that when a quality objective or quality standard established pursuant to relevant EU legislation requires stricter conditions, more stringent emission controls must be set accordingly. (Art 10.)
For many Member States this has required fundamental adjustments of their regulatory approach since releases of pollutants have traditionally been controlled by either one of these two control mechanisms, rather than by a combination of the two instruments.
-  Commission Directive 2009/90/EC laying down, pursuant to Directive 2000/60/EC of theEuropean Parliament and of the Council, technical specifications for chemical analysis and monitoring of water status  OJ L 201/36.