This dataset comprises water quality data from the NIEA water quality database from 1st January 1990 to 31st December 2024. Note that the dataset may contain results which are erroneous due to typos, sampling error or contamination. Such data points are usually several orders of magnitude above expected values. This is one of a series of water datasets being made available as Open Data. Other NIEA datasets remain available on request via waterinfo@daera-ni.gov.ukThe European Water Framework Directive (2000/60/EC) has been transposed into Northern Ireland Regulations through The Water Environment (Water Framework Directive) Regulations (Northern Ireland) 2017. The Water (Amendment) (Northern Ireland) (EU Exit) Regulations 2019 ensures that the Water Framework Directive (WFD) (as transposed) and the various supporting pieces of water legislation continue to operate here after 1 January 2021. The regulations encourage the active involvement of interested parties and the general public. The regulations set out the requirement to achieve 'Good Ecological Status' and 'Good Chemical Status' for all ground and surface waters (rivers, lakes, transitional waters, and coastal waters) within Northern Ireland.Surface waters are assessed according to the following criteria: biological quality (fish, invertebrates, flora), hydromorphological, physico-chemical properties like temperature, oxygenation and nutrient conditions, chemical quality assessed against environmental quality standards for specific pollutants and priority substances.The following physico-chemical and chemical parameters are included in the dataset:ALK (mg/l) - AlkalinityBOD (mg/l) - Biochemical oxygen DemandCOND (uS/cm) - ConductivityD_Cu (ug/l) - Copper, DissolvedD_FE (mg/l) - Iron, DissolvedDO (mg/l) - Dissolved OxygenNH4-N (mg/l) - AmmoniaNO3-N (mg/l) - NitrateNO2-N (mg/l) - NitriteP(SOL) (mg/l) - Phosphorus, Soluble Reactive (SRP)PH - pH ValueSS (mg/l) - Suspended solidsZN SOL (ug/l) - Zinc, Dissolved