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TWD (Tap Water Database) is designed as a reference and informational tool. It presents reported water quality data in a clear and accessible format to support general understanding of tap water testing results. TWD provides public access to tap water quality information across Canada. The Database aggregates and displays publicly available water testing data to allow users to explore reported contaminant levels by location.
City markers are colour-coded for visual reference only, based on how reported contaminant values compare to selected reference benchmarks. Colour indicators are not safety determinations, do not indicate regulatory compliance or non-compliance, and should not be interpreted as health advice.
TWD displays contaminant data alongside different reference points for comparison purposes. Health Canada Guidelines: Government-issued reference values for drinking water contaminants. Ideal Standards: Voluntary, non-regulatory reference benchmarks shown for contextual comparison only. Benchmarks are provided to help users understand how reported values compare to different reference frameworks. They are not recommendations and do not imply health risk or safety conclusions.
Average shows the mean contaminant level over time, giving you a general sense of water quality over the applicable reporting period. Peak shows the highest single measurement recorded. TWD uses peak values for visual reference because reported values are historical and may vary over time.
TWD uses peak values (the highest recorded measurement) rather than averages for visual reference. If a peak value exceeded Health Canada guidelines at any point in the reported data, the visual indicator is set to "Breached" even if the average appears within guidelines. This reflects the highest reported value in the available data.
Breached (Red): Peak value exceeds Health Canada guidelines in the reported data. Elevated (Orange/Yellow): Peak value exceeds Ideal standards but is within Health Canada guidelines in the reported data. Minimal (Green): All reported values are within both Health Canada and Ideal standards. These are visual references only and do not indicate regulatory compliance or non-compliance, safety, or health risk.
Click on any city marker, or use the search bar to find specific cities, to explore available water quality data, reported contaminant levels, and source reports.
The gauge shows what percentage of contaminants were tested compared to the total number of Health Canada guidelines. The "Tested" vs "Not Tested" labels show how many contaminants were actually measured in the available reports.
TWD displays data for over 100 contaminants including lead, arsenic, chlorine, bacteria, heavy metals (mercury, cadmium), chemical compounds, and many others, as reported in publicly available water quality reports. You can view all tested contaminants for each city in the "All Contaminants" section.
All data is sourced from publicly available records, including governmental and municipal sources. Information is provided without any guarantee as to accuracy, completeness, or currency and may be updated or corrected from time to time without notice. The information is updated as new reports become available, typically monthly or quarterly depending on the city's testing schedule.
TWD currently displays data for major cities across Canada where publicly available water quality reports exist. The database is updated as more water quality reports become available.
Key Contaminants are contaminants displayed with their peak values and visual indicators. These are typically contaminants where reported peak values exceeded reference benchmarks or showed the highest reported levels in the available data.
TWD is a Progressive Web App (PWA) that works offline. After your first visit, the app caches data and you can view previously accessed city information even without an internet connection.
TWD is a Progressive Web App. On mobile devices, you can add it to your home screen for a native app-like experience. Look for the install prompt or use your browser's "Add to Home Screen" option.
TWD is available for public use at no cost.
The "View Report" button allows you to request a PDF document containing reported water quality data for a selected city. The report presents publicly available water testing data in a formatted document, including reported contaminant levels, visual charts showing historical data points, and reference benchmarks for comparison. Reports are provided for informational and reference purposes only. The information presented reflects historical reported data and may not reflect current conditions. Reports are delivered via email and contain the same data available in the TWD interface, formatted for reference purposes.