Environment Agency Hydrology Data API

Environment Agency Hydrology Data API

England's Environment Agency publishes its hydrological records over a keyless API. The reference says: "The Hydrology API provides access to historic and recent hydrological data including river flows, river levels, groundwater levels, rainfall and water quality."

Coverage

Monitoring stations, measures and readings for river flow, river level, groundwater level, rainfall and water-quality parameters (dissolved oxygen, fluorescent dissolved organic matter, blue-green algae, turbidity, chlorophyll, conductivity, temperature, ammonium, nitrate and pH), at 15-minute and daily resolution depending on the parameter. The reference says the service "provides data from nearly eight thousand monitoring stations, and includes sub-daily (typically 15 min) resolution time series as well as wider range of daily time series" and "provides access to over four billion rows of readings." Responses are available as JSON, CSV, HTML, RDF, Turtle and GeoJSON, and a batch API queues larger requests.

Verdict

England's river flow, river and groundwater level, rainfall and water-quality readings, historic and recent, over a keyless API. The licence is published inside the API itself: the reference says "The metadata description included in JSON and RDF results provides information about the API, such as the publisher and applicable licence.", and the stations response read on 2026-11-09 gave "licenseName": "OGL 3" with a nationalarchives.gov.uk Open Government Licence v3.0 link; the service's own footer says "All content is available under the Open Government Licence v3.0, except where otherwise stated". Volume limits are published instead of a request rate: "The API calls that return readings data have a soft limit of 100,000 rows per-call which can be overridden by setting a _limit parameter." and "However, we current set a hard limit of 2,000,000 rows, which cannot be overridden." For bulk use the Agency asks: "Ideally limit to one request in flight at a time, waiting for each request to finish before issuing the next." Distinct from ea-flood-monitoring-api, which serves real-time flood warnings and levels. Signal Lab links only.