Data Sources

Health-based test results

The core dataset — E. coli, lead, fluoride, trihalomethanes, haloacetic acids, and NDMA, with up to nine years of history per city — comes from the Ontario Ministry of the Environment, Conservation and Parks' Drinking Water Quality and Enforcement dataset, published under the Open Government Licence – Ontario. We process the raw regulatory test results into per-city, per-year summaries; the figures shown here are not official Ministry publications themselves.

Aesthetic parameters

Hardness, sodium, pH, alkalinity, and chlorine/chloramine are not part of Ontario's centralized health-based dataset. Where shown, these figures are sourced directly from each municipality's own published annual water quality report, one region at a time, and are dated separately from the nine-year fiscal-year series above.

Methodology audit

The running annual average calculations used for trihalomethanes and haloacetic acids can be verified row-by-row in the published RAA methodology CSV.

Independent project

Find My Drink is an independent project. It is not affiliated with, endorsed by, or operated on behalf of the Government of Ontario or any municipality. If you need current water advisory information, contact your municipal water utility or Ontario's official sources directly.

See How to read the data for how these figures are summarized and presented.