A new report has ranked the Ontario school boards and schools with the highest number of lead exceedances in drinking water tests.
The report was released by the Canadian Environmental Law Association and examined water test results from the 2024–25 school year.
Researchers reviewed publicly available data and identified schools and school boards where lead levels exceeded Ontario’s legal limit of 10 parts per billion and Health Canada’s recommended limit of five parts per billion.
According to the report, the Ottawa-Carleton District School Board recorded the highest number of exceedances among school boards, with 104 tests over 10 parts per billion and 156 tests above five parts per billion.
Other school boards with high numbers of exceedances included the Dufferin-Peel Catholic District School Board, the Toronto District School Board and the Peel District School Board.
The study reviewed results from 83 public school boards, school authorities and provincially run schools across Ontario.
At the individual school level, Beaver River Public School in the Durham District School Board ranked first for the number of tests exceeding the limit.
Other schools on the list included Val Des Bois School, Orleans Wood Elementary School, Fallingbrook Community Elementary School and Major Ballachey Public School.
Additional schools listed were St. Francis of Assisi School, Easthill Elementary School, Sherwood Secondary School, Manor Park Public School and St. Kevin School.
The report said the number of exceedances could be higher than reported because some schools qualify for testing exemptions, which may reduce the total number of samples collected.
Researchers also noted that the total exceedance numbers may include multiple tests from the same tap.
The report raised concerns about potential health risks for children, noting that even small amounts of lead exposure can be harmful. Experts say no level of lead exposure is considered safe, especially for young children.
The organization is calling on the Ontario government to update its approach to monitoring drinking water in schools, improve transparency and work toward eliminating lead exposure over the long term.
Ontario currently allows lead levels of up to 10 parts per billion before action is required. Only Ontario and Saskatchewan have this higher threshold, while Health Canada recommends a lower limit of five parts per billion.
In response, the provincial government said Ontario already has one of the most comprehensive testing and mitigation systems for lead in school drinking water.
Officials also stated that there have been no reported cases of lead poisoning in children caused by drinking water in Ontario schools during the past decade.
The report also points parents and the public to an online database developed with researchers at the University of Toronto that allows users to review lead test results for schools and daycare centres across the province.