The Water Quality Explorer provides access to the Environment Agency’s water quality data collected from tens of thousands of sampling points across England. The dataset covers all major water body types, including rivers, lakes, ponds, canals, groundwater, and coastal and estuarine waters, and includes over 72 million observations derived from over 5 million samples collected since the year 2000.
These observations include both field measurements taken in situ at sampling locations and a wide range of laboratory‑analysed parameters assessed in the Environment Agency’s laboratories. Once samples have been analysed, the results are processed and verified before being added to the archive, meaning there is a short delay between a sample being taken and the corresponding data becoming available.
The dataset spans a broad suite of determinand groups, including: Physical parameters (such as temperature, pH, conductivity, turbidity, and salinity in coastal or estuarine waters), nutrients and general water chemistry (including nitrate, ammoniacal nitrogen, and dissolved oxygen), metals (such as iron, zinc, copper, nickel, and lead), organic, inorganic and emerging contaminants (including hydrocarbons, pesticides, and PFAS), and sediment characteristics (including grain size fractions and related particle size metrics).
The dataset is updated within two working days of a new sample being added. In addition, a complete monthly data refresh is carried out, which may include corrections or refinements to previously published data to ensure users have access to the most accurate records. Attribution statement: © Environment Agency copyright and/or database right 2025. All rights reserved.