One of the first things we learned building this site: neither the United States nor Canada maintains a single, unified “boil water advisory” feed, and the two countries do not share one common database either. Data is fragmented by design, so here is the honest map.
The U.S. patchwork
In the U.S., the Safe Drinking Water Act makes the water system itself responsible for notifying customers, usually within 24 hours, and states with primacy (almost all of them) enforce that duty. That means the ground truth lives with tens of thousands of local utilities. A few states publish genuinely machine-readable feeds — Alaska’s DEC runs a live ArcGIS service straight from its SDWIS database, and Florida’s Department of Health compiles a running notice list — while others post PDF lists, interactive maps, or nothing statewide at all. EPA’s SDWIS federal database captures compliance history, not minute-by-minute advisories.
The Canadian patchwork
Canada regulates drinking water provincially. Québec publishes a consolidated advisory list, Manitoba maps its advisories on official ArcGIS services, Nova Scotia offers its full advisory history as open data, and Indigenous Services Canada tracks short- and long-term advisories in First Nations communities federally. B.C. spreads advisories across five regional health authorities. There is no cross-country API — but there is more open data than most people realize.
What we connect to
Our sync engine pulls every official machine-readable feed we could verify — ArcGIS services, Socrata open data endpoints and parseable agency pages — on a schedule, deduplicates notices, and auto-lifts advisories when the source stops listing them. Everywhere else, region pages link you straight to the authority that issues notices. If you know of an official feed we missed, tell us and we will add it.