The Government of the Northwest Territories (GNWT) has received follow-up lead testing results for École William McDonald Middle School and Range Lake North School. These results are part of an ongoing assessment of lead in school drinking water systems being conducted by engineering and environmental consulting firm Stantec, which began earlier this spring following initial concerns about water quality. A final report summarizing the findings and next steps is expected shortly.

Stantec’s final report will include a detailed summary of the sampling methods and an analysis of the results, including how the measured lead levels compare to Health Canada’s guidelines for safe drinking water.

While mitigation measures have been in place since late May, recent testing has confirmed elevated lead levels at École William McDonald Middle School and indicated that precautionary flushing will likely be needed at Range Lake North School. In response, the Chief Public Health Officer has issued Health Orders to formalize the existing mitigation measures at both schools.

Two types of tests were conducted over the past few weeks.

• Random sampling was done on the afternoon of May 27, 2025, to reflect typical daytime water use.
• Exceedance protocol testing was conducted on June 12 and June 13 to “stress test” the system under conditions that are more likely to result in higher lead levels. The goal of the protocol was to help identify possible sources of lead and inform long-term mitigation planning.

Results from the random sampling showed that Range Lake North School had lead levels below Health Canada’s guideline of 5 micrograms per litre (µg/L). At École William McDonald Middle School, 6 of the 13 outlets tested were below the guideline, 5 measured between 5 and 10 µg/L, and 2 were above 10 µg/L.

For results from the exceedance protocol testing, please refer to the backgrounder.

Further work is needed to identify the source of elevated lead levels at École William MacDonald Middle School. Investigations will continue to determine the cause and to identify appropriate mitigation and remediation measures. The water system will remain closed for drinking until these steps are completed.

Samples from Range Lake North School indicate that a flushing protocol (running water to flush any stagnant water prior to drinking) will be required.

The Chief Public Health Officer (CPHO) has issued orders to Yellowknife Education District No.1 (YK1) formalizing the “do not consume” actions that were already in place for both schools since May 27. The Office of the CPHO will be monitoring all sampling results and remediations and will not remove these orders until requirements are met.  

Mitigation measures include removing affected drinking water sources and providing alternative safe drinking water as a precaution. Alternative water supplies will remain in place until the order requirements are met.

Most children who have lead in their blood do not show immediate symptoms. However, even low levels of lead can result in subtle neurodevelopmental issues, particularly in young children. Preschool children can absorb approximately 40% of the lead they happen to ingest, while adults absorb only about 10%.

If you are concerned about elevated lead levels, please contact Primary Care by completing the Callback Request Form and select 'YK Primary Care Regarding Public Health Order'. The NTHSSA is currently working to assign specific staff to manage these needs, streamline the process and expand appointment availability. By completing the Callback Request Form, Primary Care Assistants can more efficiently manage scheduling and clinic capacity. They will follow up with you directly to book an appointment where your blood work can be done during the same visit, eliminating the need for separate trips to primary care and the lab, as is usually required. Based on the level of need, a future pop-up clinic may also be scheduled.

Recent health monitoring in the NWT, conducted by the University of Ottawa and the University of Waterloo as part of the Health Effects Monitoring Program, tested residents of Yellowknife, Ndılǫ, and Dettah from 2017 to 2024. This program found that blood lead levels in children and adults are generally low and well below public health intervention thresholds.

There are no concerns about lead in the municipal drinking water in Yellowknife or other municipal drinking water supplies across the Northwest Territories. Regulatory testing completed in 2023 and 2024 confirmed it meets all safety standards.

For general health questions, residents can call 811 to speak with a registered nurse or visit the Health and Social Services website for more information.

The GNWT is committed to transparency, accuracy, and accountability. We understand that many families, educators, and community members will have questions. While the final Stantec report is still pending, this update reflects test results that support the continuation of existing mitigation measures. We will continue to keep residents informed and will share verified updates — including the final report — as soon as they are available.

See attached PDF for results from the exceedance protocol.

For more information, visit: https://www.hss.gov.nt.ca/en/services/environmental-contaminants/lead-and-your-health   

For media requests, please contact:
Agata Gutkowska
Manager, Public Affairs and Communications
Education, Culture and Employment
Government of the Northwest Territories 
Agata_Gutkowska@gov.nt.ca
867-767-9352 ext. 71073

Umesh Sutendra
Acting Manager, Communications
Health and Social Services
Government of the Northwest Territories
HSSMedia@gov.nt.ca