{"id":"england-groundwater-levels","slug":"england-groundwater-levels","name":"England Groundwater Level Dataset","description":"Monthly and annual groundwater levels at long-record observation boreholes in England, in metres above Ordnance Datum. The Chilgrove House borehole in the South Downs chalk has been dipped since 1836.","methodology":"Manual dipped water-table elevations are read from the Environment Agency Hydrology Data Explorer and averaged by month. Dipped readings are taken by hand, typically weekly or monthly, so a monthly figure may rest on a single reading and represents the level observed in that month rather than a continuous average. Readings impossible for their own borehole — beyond the series median by more than the greater of 50 m and twelve interquartile ranges — are rejected, because a global plausible range cannot catch a level that is ordinary under Trafalgar Square and impossible in the Sussex chalk.","domains":["groundwater"],"metricIds":["groundwater-level"],"subjectScope":"English observation boreholes with a record opening before 1970","cadence":"monthly","version":"1.0.0","released":"2026-08-24","changelog":[{"version":"1.0.0","date":"2026-08-24","summary":"First release.","additions":["Monthly and annual levels for 409 long-record English boreholes."]}],"limitations":["Levels are specific to a borehole and its aquifer and must be read against that borehole’s own historic range. Absolute elevations from different boreholes are not comparable with one another.","A level below zero is ordinary where the water table sits below sea level, and is not an error.","Sampling is manual and irregular; a month with one reading and a month with five are both published as that month’s level."],"observationCount":189904,"seriesCount":782,"subjectCount":409,"from":1836,"to":2026,"sourceIds":["uk-ea-hydrology"],"units":["m"],"redistributable":true,"commerciallyReusable":true,"citation":"Hydrionis (2026), England Groundwater Level Dataset, version 1.0.0. Retrieved from https://hydrionis.com/data/datasets/england-groundwater-levels/","downloads":[{"file":"/downloads/observations-groundwater-uk-ea-hydrology.csv","format":"CSV","label":"groundwater observations from EA (193,032 rows)"}],"apiPath":"/api/v1/datasets/england-groundwater-levels.json","lastFetched":"2026-10-01","fields":[{"id":"groundwater-level","name":"Groundwater level","definition":"Elevation of the water table or piezometric surface at a monitoring borehole.","unit":"m","nativeGeography":["borehole"],"comparabilityNotes":"Levels are specific to a borehole and its aquifer, and must be read against that borehole’s own historic range. Absolute elevations from different boreholes are not comparable."}]}