By Masih Khalatbari, Dori Seeman

Dangerous levels of lead continue to threaten children’s health in Ontario. The IJB database of lead levels in the drinking water of schools and daycares across the province has been updated to include six years of findings drawn from drinking water taps. 

The IJB reviewed more than 175,000 lead test results between 2019 and 2025. Overall, one in 10 tests exceeded the federal guideline, and more than half of Ontario’s public schools had at least one test that exceeded the federal objective. A similar trend follows in child care centres and private schools, where more than 27 per cent and 16 per cent have at least one test exceeding the federal guideline, respectively.

No amount of the neurotoxin in water is safe for children, according to the World Health Organization. Even low levels are linked to decreased IQ and attention span, motor skill weakness and behavioural problems.

Yet, hundreds of these problematic results will not be addressed by the Ontario government or even be flagged to students and parents by school boards. That’s because Ontario uses a lead safety guideline of 10 parts per billion (ppb) – double that of the federal guideline of five ppb established seven years ago. The federal safety guideline – considered a more accurate measure of the health risks of lead – has already been adopted by nearly every other province in Canada. But Ontario and Saskatchewan continue to use what experts call an outdated and dangerous level to measure the safety of drinking water in public and private education.  

In the 2024/25 testing year alone, 599 tests exceeded the federal guideline but not Ontario’s more lax guideline, meaning schools and daycares will not address those taps and fixtures because the readings do not reach the province’s threshold of safety concern. 

Ontario’s Ministry of Environment, Conservation and Parks, which is responsible for setting and enforcing lead safety guidelines in water for the province, did not respond to a detailed set of questions in time for publication.

Earlier this year, a ministry spokesperson said schools, private schools, and childcare centres are “required to flush their plumbing on a daily or weekly basis, depending on the most recent fixture test results.

“Where lead levels exceed the provincial drinking water quality standard (10 ppb), facility owners … must take immediate corrective action as directed by the local medical officer of health,” said Lindsay Davidson of the Ontario Ministry of the Environment and Climate Change.

“This approach has ensured there have been no reported cases of lead poisoning in children due to drinking water in the last 10 years.”

There is no routine testing for lead in Canadian children’s blood. And even low-level exposure can have harmful effects on children’s brain development without obvious signs of toxicity, according to a 2019 position statement by the Canadian Pediatric Society.

By The Numbers

Search the Updated Database