252,857
Observations
18,060
Series
4,846
Subjects
2000–2025
Period covered

Methodology

Individual sample results are read from the Water Quality Archive and reduced to annual figures per monitoring point. Results the laboratory reported as below its detection limit are excluded from the mean rather than counted as their limit or as zero, and a year is published only where such results were fewer than half of it and at least eight samples were taken. pH is published as an annual median rather than a mean, because the scale is logarithmic and arithmetic averaging of it is not a valid operation. Nutrients keep the basis the Environment Agency reports them on — nitrate as nitrogen, orthophosphate as phosphorus — in their own metrics, rather than being converted into the ionic basis used by drinking-water standards.

What this dataset cannot tell you

Coverage

SubjectsEnglish freshwater river monitoring points with at least ten years of record4,846 held
Period20002025
Units%, mg/l, mg/l as N, mg/l as P, pH
Update cadenceAnnually
Identifierengland-river-water-quality v1.0.0

Every metric this dataset carries, with the unit it is stored in and the geography level it is reported at. Full definitions are in the data dictionary.

IdentifierFieldUnitReported at
nitrate-as-nNitrate as nitrogen
Concentration of nitrate in water expressed as the mass of nitrogen it contains, the convention used in environmental monitoring.
mg/l as Nmonitoring-station
orthophosphate-as-pOrthophosphate as phosphorus
Concentration of reactive orthophosphate expressed as the mass of phosphorus it contains.
mg/l as Pmonitoring-station
ammoniacal-nitrogenAmmoniacal nitrogen
Combined concentration of ammonia and ammonium expressed as the mass of nitrogen, a standard indicator of recent organic or sewage pollution.
mg/l as Nmonitoring-station
dissolved-oxygenDissolved oxygen
The concentration of oxygen dissolved in water, essential for aquatic life.
mg/lmonitoring-station, river-gauge
dissolved-oxygen-saturationDissolved oxygen saturation
Dissolved oxygen expressed as a percentage of the maximum the water could hold at its temperature and pressure.
%monitoring-station, river-gauge
phpH
The negative logarithm of hydrogen ion activity, measuring how acidic or alkaline water is.
pHmonitoring-station, supply-zone

Rights and access

Licence position

Open with attribution. Derivative use true; redistribution true; commercial reuse true.

Attribution required:

  • Contains public sector information licensed under the Open Government Licence v3.0.

Permitted uses

  • Public display
  • Derived analysis
  • API delivery
  • Bulk download
  • Commercial use

Available to: Public, Developer, Research, Professional, Enterprise. These follow from the rights of the contributing publishers, not from a Hydrionis pricing decision — no access tier can widen what a publisher withheld.

Contributing sources

Suggested citation

Hydrionis (2026), England River Water Quality Dataset, version 1.0.0. Retrieved from https://hydrionis.com/data/datasets/england-river-water-quality/

Cite the version. Hydrionis datasets change as publishers release and as methods are revised, and a citation without a version cannot be checked later.

Changelog

Version 1.0.0 — 2026-08-24

First release.

Additions

  • Annual values for six determinands at 4,846 English river monitoring points.

Getting the data

Machine-readable metadata for this dataset is at /api/v1/datasets/england-river-water-quality.json. For bulk extracts, higher-volume access or commercial licensing, see data enquiries.