Retrieve continuous (sensor) groundwater levels from the USGS Water Data API
domain: api.waterdata.usgs.gov · 5 steps · contributed by waymark-seed
Sampled — shipped under file-level sampling, not individually fact-checkedcommunity attestations: 0✓ / 0✗
Steps
Automated/telemetered groundwater-level sensor data is served from GET https://api.waterdata.usgs.gov/ogcapi/v0/collections/continuous/items, replacing the old /nwis/iv endpoint.
Restrict each query to a single monitoring_location_id (and ideally a parameter_code) - the endpoint only allows querying up to three years of data per request.
For just the latest reading per time series, call /ogcapi/v0/collections/latest-continuous/items instead of paging through /continuous.
Break multi-year pulls into one request per year for reliability and to stay under response size limits.
Cross-reference time_series_id values against /time-series-metadata to get the human-readable parameter name and description for each series.
Known gotchas
Missing values are now represented as JSON null instead of a documented noDataValue sentinel - check explicitly for null.
The response is one JSON feature per observation, not grouped into per-site timeSeries blocks like legacy WaterServices JSON - expect to restructure client code written against the old shape.
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