Location-level swim-safety data for 13,126 lakes and beaches across the United States, combining satellite cyanobacteria monitoring and beach bacteria advisories into a single plain-language verdict for each water.
Maintained by SwimZone, a free daily swim-safety check for lakes and beaches. This dataset is the open snapshot behind the site. See the methodology for how each water is scored.
One row per water body.
| Column | Description |
|---|---|
name, slug |
Water body name and the URL slug used on swimzone.app |
type |
lake or beach |
state, state_name |
US state (postal code and full name) |
county |
County name, where known |
lat, lng |
Representative coordinate |
monitored |
true if the water has an active monitoring source |
monitoring_source |
e.g. EPA CyAN satellite, EPA BEACON |
status_band |
Overall snapshot verdict: safe / caution / unsafe / unknown |
cyano_band |
Cyanobacteria (harmful algal bloom) band for the snapshot |
bacteria_band |
Bacteria advisory band for the snapshot |
snapshot_date |
Date of this snapshot |
The *_band and snapshot_date columns are a daily snapshot and change over time; the identity columns (name, type, location, monitoring source) are stable.
- Cyanobacteria / harmful algal blooms: EPA Cyanobacteria Assessment Network (CyAN) satellite imagery (public domain).
- Beach bacteria advisories: EPA BEACON / state beach-monitoring programs (public domain).
- Place identifiers and geography derived from public government sources.
The verdict bands are SwimZone's own synthesis of the above. Upstream federal data is public domain; this derived dataset is released under CC BY 4.0.
Creative Commons Attribution 4.0 International (CC BY 4.0). See LICENSE.
SwimZone (2026). SwimZone Water Quality Dataset. https://swimzone.app