Data Sources
Every dataset used by the PFAS Watchlist. All sources are official U.S. government publications. No commercial, NGO, or non-government sources are used.
Pipeline Status
Official Sources Used
EPA UCMR 5 Occurrence Data
U.S. Environmental Protection Agency
Primary PFAS monitoring data source. All displayed PFAS occurrence records originate from this dataset.
Refresh cadence
Released by EPA as UCMR 5 monitoring data is finalized. Check EPA page for latest release date.
Terms
Publicly released U.S. government data.
Key fields used
EPA Safe Drinking Water Information System (SDWIS)
U.S. Environmental Protection Agency
Canonical utility registry. Used to match PWSID to utility name, service area, population served, and system type.
Refresh cadence
Ingested quarterly.
Terms
Publicly released U.S. government data.
Key fields used
EPA ECHO — Enforcement and Compliance History Online
U.S. Environmental Protection Agency
Supplemental official enforcement context. Referenced by direct link for per-utility official enforcement records.
Refresh cadence
Referenced by direct link; not bulk-ingested into this system.
Terms
Publicly released U.S. government data.
Key fields used
Disallowed Sources
The following source types are never used in this watchlist, regardless of their content quality or reputation:
- Commercial databases or data aggregators
- Environmental or advocacy NGOs
- News stories or journalism
- Utility marketing pages or CCR summaries
- Crowdsourced or community-contributed data
- University or academic summaries (unless republished by a government authority)
- Modeled or inferred contamination risk data (unless published by a government authority and clearly labeled as modeled)
- Private laboratory result databases or marketplaces