These Regulations amend the European Communities Environmental Objectives (Surface Waters) Regulations 2009. They give effect to: Commission Implementing Decision (EU) 2018/229 establishing, pursuant to Directive 2000/60/EC of the European Parliament and of the Council, the values of the Member State monitoring system classifications as a result of the intercalibration exercise and repealing Commission Decision 2013/480/EU; and Commission Implementing Decision (EU) 2018/840 establishing a watch list of substances for Union-wide monitoring in the field of water policy pursuant to Directive 2008/105/EC of the European Parliament and of the Council and repealing Commission Implementing Decision (EU) 2015/495. The Regulations update existing environmental standards used in the assessment of ecological status, mainly by providing additional boundary values for existing environmental quality standards and the inclusion of a new environmental quality standard for total phosphorus in lakes. They also provide for an updated watch list to monitor concentrations of emerging pollutants and other substances of concern in the aquatic environment.