Data sources
Everything here comes from Ontario open data. Two sources feed today’s pages; three more are held for later.
Ontario drinking-water framework
Open data on this site is provincial. Day-to-day compare lines (hardness, sodium, chloride, nitrate, fluoride, pH) follow Ontario’s framework — see ontario.ca drinking water, O. Reg. 169/03, and our plain map: Ontario drinking-water standards.
Quality & enforcement records On this site
Official name: Drinking Water Quality and Enforcement
In plain words: Public testing flags, inspections, reported water problems, orders, and related notes for regulated drinking-water systems — published by year.
How we use it: Drives the status at the top of city and system pages, and the “closer look” counts.
Do not assume: History in the public file — not a full list of every substance, and not live alerts.
Day-to-day lab samples (selected systems) On this site
Official name: Drinking Water Surveillance Program (DWSP)
In plain words: Lab measurements such as hardness and sodium for systems that took part in this program.
How we use it: Day-to-day cards on system pages when samples exist.
Do not assume: Not every system is in the program. Missing cards mean no samples here — not a warning.
Lake water at intakes Not yet used
Official name: Lake Water Quality at Drinking Water Intakes
In plain words: Long-term lake monitoring at Great Lakes drinking-water intakes.
How we use it: Not on public pages yet. Possible later context for lake-supplied systems.
Do not assume: Raw lake water is not treated tap water.
Groundwater monitoring Not yet used
Official name: Provincial Groundwater Monitoring Network
In plain words: Groundwater levels and chemistry from monitoring wells across Ontario.
How we use it: Not on public pages yet. Possible later private-well / groundwater area.
Do not assume: Monitoring wells are not household taps.
Well construction records Not yet used
Official name: Well Records
In plain words: Construction records for water wells across Ontario.
How we use it: Not on public pages yet. Possible later private-well area.
Do not assume: Drilling and construction history — not water-quality tests.
Licence
Source data is published by the Government of Ontario under the Open Government Licence – Ontario. This site is not a government site. If our summary and the official file differ, the official file is correct.