US Public Water Systems Registry (SDWIS/SDWA)

Registry of the nation's public water systems from EPA's Safe Drinking Water Information System (SDWIS), published through the Enforcement and Compliance History Online (ECHO) bulk download. One row per active or formerly active public water system identified by its PWSID (Public Water System Identifier): name, primacy agency (usually the state), EPA region, system type (Community, Transient Non-Community, Non-Transient Non-Community, or Non-Public), ownership, population served, service connection count, and contact/address details. Covers roughly 160,000 public water systems nationwide, of which about 50,000 are Community Water Systems (CWS, `pws_type_code = 'CWS'`) serving an estimated 300 million people year-round. The other system types are Transient Non-Community (TNCWS, e.g. gas stations, campgrounds), Non-Transient Non-Community (NTNCWS, e.g. schools, factories with their own well), and Non-Public (NP). This file is a current snapshot, not an accumulating time series: each PWSID appears exactly once per download, carrying its latest reported values as of `quarter`. ECHO republishes the full snapshot quarterly, so `quarter` marks the vintage of a given sync rather than a per-row historical period. This dataset covers only the public water systems registry (SDWA_PUB_WATER_SYSTEMS.csv) from the larger SDWA bulk download, which also includes separate violations, enforcement, site visit, and sampling tables not ingested here.

Source rows:

434,757

Coverage:

1900-02-01T00:00:00Z – 2031-05-29T00:00:00Z