Library
The State Water-Data Atlas
How much public water monitoring does each state actually have? This atlas compares all 50 states by what the USGS national monitoring network is actively measuring — stream levels, groundwater depths, water chemistry, and more. Every number on this page was counted from the public record on the date shown, and the method is stated so anyone can reproduce it.
All 50 states — active monitoring sites by parameter
Each cell counts the USGS sites in that state actively reporting that parameter — sites, not series, so one sensor counts once. Shading is scaled within each column. Click a heading to rank states by that parameter.
Where public boring logs live in the Southeast
Drilling and boring logs rarely live in the USGS system — they live in each state environmental agency’s public document repositories. We verified each source below on August 12, 2026 by downloading a real document and reading an actual boring-log sheet inside it.
How to read this honestly
- USGS only. The census covers the USGS national system. State-run networks are invisible to it — South Carolina, for example, shows 27 active USGS groundwater sites while its state agency separately operates a network of roughly 180 wells.
- “Active” means the site reported data on or after January 1, 2025.
- Level as elevation combines the USGS codes that publish water level as a datum elevation (stream, lake, and groundwater variants).
- Column-relative shading: the darkest cell in a column is that column’s maximum, so shades compare states within one parameter, never across parameters.
- Sources: USGS OGC time-series-metadata API (50-state census, August 3, 2026) and the USGS NWIS site service (groundwater site counts, August 12, 2026), plus the state document repositories linked above — all public, all reproducible.