National Wastewater Drug Surveillance (NWDS): Overview
An interactive dashboard to explore the presence of drugs, their byproducts (metabolites), and related precursor chemicals based on the collection of samples from wastewater sites located across Canada.
- Last updated: 2025-11-17
Through the National Wastewater Drug Surveillance (NWDS) initiative, Health Canada analyzes wastewater samples for the presence of drugs, drug metabolites and precursor chemicals. Wastewater analysis can tell us about the type of drugs being used in different locations across Canada.
These results represent likely drug candidates in wastewater and are indicative rather than definitive. They should therefore be used with caution when assessing trends or drawing conclusions about drug use in Canada. For more information on data limitations, please see the Understanding the Data page.
We collected influent wastewater samples from January to December 2023 and from April 2024 to July 2025. We analysed 239 monthly representative samples during these 2 periods.
Key highlights
Overview: Text description
The following figures summarize the:
- Substances detected most often
- Number of distinct substances identified by pharmacological class
Substances may be detected across multiple sites and provinces or territories and do not represent individual use.
The map, interactive figures, and table on this page show the substances that were identified. Where the feature is available, select a time period, province or territory, pharmacological class or multiple filters from the dropdown menus on the left to update the results
This figure shows the number of distinct substances identified in each province and territory. The same substance can be identified across the regions. If you select an individual substance from the dropdown menu, the figure will show the number of identifications of that substance for each province or territory.
Hover over or select a portion of the map to find the number of distinct substances identified, or the number of identifications of a specific substance, as well as the number of sites for each province or territory.
Figure 1: Text description
| Province/Territory | Number of distinct substances |
|---|
Figure 1: Notes
- On this page, metabolites are grouped with their parent substance. Metabolites are only grouped with their parent substance if they are exclusively a metabolite. Also, metabolites are grouped with their parent substance only if they are exclusive metabolites of that substance. In some cases, a substance may be a metabolite or a parent substance. For example, hydroxymethamphetamine is both a metabolite and a parent substance, therefore it is displayed on this page. All metabolites of a given parent substance are only counted once per monthly representative sample and are referred to as their parent substance. In some cases, we do not screen for the parent substance itself, but instead we screen for its metabolite. For example, to identify nicotine, we screen for its metabolite, cotinine. However, on this page, we use the parent substance names. To explore which specific metabolites were identified in the wastewater, refer to Figure 5 on the Metabolites tab.
This figure shows the number of distinct substances identified by their pharmacological class.
Figure 2: Text description
| Pharmacological class | Number of distinct substances identified |
|---|
Figure 2: Notes
- On this page, metabolites are grouped with their parent substance. Metabolites are only grouped with their parent substance if they are exclusively a metabolite. Also, metabolites are grouped with their parent substance only if they are exclusive metabolites of that substance. In some cases, a substance may be a metabolite or a parent substance. For example, hydroxymethamphetamine is both a metabolite and a parent substance, therefore it is displayed on this page. All metabolites of a given parent substance are only counted once per monthly representative sample and are referred to as their parent substance. In some cases, we do not screen for the parent substance itself, but instead we screen for its metabolite. For example, to identify nicotine, we screen for its metabolite, cotinine. However, on this page, we use the parent substance names. To explore which specific metabolites were identified in the wastewater, refer to Figure 5 on the Metabolites tab.
This figure shows the number of identifications and detection percentage of the substances that were identified most often.
Use the toggle in the figure title to switch between the number of identifications and the detection percentage.
Figure 3: Text description
| Substance | Number of identifications |
|---|
Figure 3: Notes
- On this page, metabolites are grouped with their parent substance. Metabolites are only grouped with their parent substance if they are exclusively a metabolite. Also, metabolites are grouped with their parent substance only if they are exclusive metabolites of that substance. In some cases, a substance may be a metabolite or a parent substance. For example, hydroxymethamphetamine is both a metabolite and a parent substance, therefore it is displayed on this page. All metabolites of a given parent substance are only counted once per monthly representative sample and are referred to as their parent substance. In some cases, we do not screen for the parent substance itself, but instead we screen for its metabolite. For example, to identify nicotine, we screen for its metabolite, cotinine. However, on this page, we use the parent substance names. To explore which specific metabolites were identified in the wastewater, refer to Figure 5 on the Metabolites tab.
This table shows the number of identifications, the detection percentage of each substance and their pharmacological class.
| Substance Name | Pharmacological Class | Number of Identifications | Detection Percentage |
|---|
Table 1: Notes
- On this page, metabolites are grouped with their parent substance. Metabolites are only grouped with their parent substance if they are exclusively a metabolite. Also, metabolites are grouped with their parent substance only if they are exclusive metabolites of that substance. In some cases, a substance may be a metabolite or a parent substance. For example, hydroxymethamphetamine is both a metabolite and a parent substance, therefore it is displayed on this page. All metabolites of a given parent substance are only counted once per monthly representative sample and are referred to as their parent substance. In some cases, we do not screen for the parent substance itself, but instead we screen for its metabolite. For example, to identify nicotine, we screen for its metabolite, cotinine. However, on this page, we use the parent substance names. To explore which specific metabolites were identified in the wastewater, refer to Figure 5 on the Metabolites tab.
Contact us
If you have comments or questions about the data, email us at odrs-brsd@hc-sc.gc.ca.
Footnotes
- This wastewater-based analytical method was developed to identify emerging drug trends and detect new psychoactive substances (NPS) present at low concentrations in complex wastewater matrices. As such, our reporting criteria are intentionally broad and results provided may include false positives and/or false negatives. Users of this data should interpret results with caution and consider them as indicative rather than definitive. Confirmatory testing using validated methods is recommended for any critical decision-making.
- Our wastewater program currently has limited coverage. The number of municipalities varies between provinces and territories, and the number of sites can vary from month to month. As the drugs identified do not represent all of Canada, trends should be interpreted with caution.
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