United States Geological Survey
National Water Information System
Continuous and discrete measurements of streamflow, groundwater level, water temperature and water quality from more than a million sites across the United States, with real-time telemetry from thousands of gauges.
Rights
- Commercial reuse
- Yes
- Redistribution
- Yes
- Derivative use
- Yes
- Attribution required
- No
- Restrictions
- Applies to material authored by US federal agencies. Third-party material carried within a federal product may be separately protected.
- Terms last checked
- 23 August 2026
Access and coverage
- Publisher
- United States Geological Survey
- Geographic coverage
- United States and territories
- Temporal coverage
- 1889 onwards
- Update frequency
- real-time
- Formats
- csv, json, xml, api
- Bulk download
- Available
- Registration required
- No
- Cost to Hydrionis
- Free
- Domains
- river flow, groundwater, quality, chemistry, reservoir
What Hydrionis holds from this publisher
The publisher’s own coverage is above. This is what Hydrionis has actually taken from it, at the subjects it measures — gauges, boreholes, reservoirs or places.
659,946
Values held
37,013
Series, each one measurement at one place
2,656
Subjects measured
1806–2026
Period actually held, not the publisher’s span
What is measured
- Annual maximum river flow · m³/s
- Catchment area · km²
- Depth to groundwater · m
- Mean river flow · m³/s
- Mean river flow, water year · m³/s
- Reservoir stored volume · Mm³
How current it is
- Current
- Read from USGS 4 days ago, and the newest monthly value covers 2026-09 — as current as this source gets.
- Current
- Read from USGS 4 days ago, and the newest annual value covers 2025 — as current as this source gets.
- Expected publication lag
- Hydrionis holds everything USGS currently offers — it was read 4 days ago. The newest value still covers 2026-08, further back than the 7 days an instantaneous value usually takes to appear. The publisher has not issued anything newer; the gap is its reporting schedule, not a Hydrionis failure.
- Current
- Read from USGS 4 days ago, and the newest monthly value covers 2026-09 — as current as this source gets.
Hydrionis products built from it
Where this publisher’s data reaches a reader. Each has its own page, with its licence and how to cite it.
Hydrionis Derived Climatology DatasetDatasetUnited States Flood Peak DatasetDatasetUnited States River Flow DatasetDatasetAnnual Runoff Depth DatasetDatasetUnited States Groundwater Monitoring DatasetDatasetUnited States Reservoir Storage DatasetDatasetHydrionis Gauge–Water Linkage DatasetDatasetGauge Catchment Area DatasetDataset