Toxic lead showing up in Ontario school and daycare drinking water as evidence of serious health dangers grows

By Declan Keogh, Norma Hilton, Scott Martin and Robert Cribb

In the past four years, nearly half the province’s public schools have had at least one test for toxic lead in drinking water exceed the federal safety guideline, an analysis by the Investigative Journalism Bureau has found. 

That lead-laced water could have impacted more than 800,000 students in roughly 2,300 elementary and high schools in that time even as new evidence reveals the toxin’s devastating impacts on human health.

Search for lead test results at a school or daycare in your area in Ontario below.

Meanwhile, some provinces – including Ontario, New Brunswick and Saskatchewan – have failed to adopt the tougher federal safety guideline for lead, which is designed to better reflect the health risks to children. 

In total, 13 per cent of the approximately 100,000 tests for lead in Ontario public school drinking water between 2019/20 and 2022/23 exceeded Health Canada’s safety guideline of 5 parts per billion (ppb). And 48 per cent of the 4,875 public schools in provincial lead test data logged at least one exceedance of the federal guideline.

In the province’s child-care centres, lead tests conducted in the same period showed almost four per cent — more than 1,000 — had lead levels exceeding the federal guideline. And test results in private schools show six per cent above the federal guideline.

There is no safe level of lead, according to the World Health Organization. Children are particularly vulnerable. 

Recent research shows the health impacts from the insidious neurotoxin – from lifelong developmental disabilities in children to increased blood pressure and coronary heart disease in adults – are far more dramatic than previously known.

Children around the world younger than five years lost 765 million IQ points in 2019 due to lead exposure from all sources, including drinking water, according to a sweeping 2023 study from the World Bank measuring the global human health toll from lead exposure. 

More than 5.5 million adults died from cardiovascular diseases due to lead exposure the same year, the study estimates, accounting for 30 per cent of all cardiovascular disease deaths worldwide. 

“What we are really concerned about is the young children …under five years,” said Bjorn Larsen, development economist with the World Bank and one of the authors of the report.  “These are the most vulnerable to lead.”

Five years after Health Canada lowered the maximum acceptable lead levels in drinking water to 5 parts per billion from twice that level, Ontario, New Brunswick and Saskatchewan  continue to measure safety at 10 ppb.

That higher provincial threshold cuts the official number of exceedances in half in provincial reporting, giving Ontarians a false sense of security, experts say. 

“When a public health problem is too big, the tendency is to cover it up when it seems overwhelming to deal with, rather than say, ‘Boy, we’ve got to hunker down and fix this,’” says Bruce Lanphear, a leading Canadian drinking water researcher at Simon Fraser University. 

“If you raise it as a threat, then your citizens may not feel protected. That’s part of what goes on in these deliberations.”

In an emailed statement, Ontario’s Ministry of Environment, Conservation and Parks did not respond to questions about the province’s decision not to adopt the federal safety guidelines for lead. 

“Our comprehensive legislation and strong monitoring, reporting and enforcement help ensure our drinking water is held to Ontario’s high safety standards,” reads a statement. “Furthermore, Ontario has one of the most stringent testing regimes for lead in drinking water in the entire country…. Ontario will continue to work with our partners through our comprehensive framework to protect Ontario’s drinking water from source to tap.” 

Differing provincial and federal lead safety guidelines paint two very different portraits of risk, the IJB analysis shows. 

Based on all Ontario tests in all schools and daycares over the past four years, about five per cent of results exceeded the provincial guideline of 10 ppb. Using the national guideline, exceedances more than double to 11 per cent.

“What we have is too high and it’s masking the scope of the problem,” said Jacqueline Wilson, counsel at the Canadian Environmental Law Association (CELA), about the lead guidelines used in Ontario. 

“It is a real equity problem,” Wilson said. “It affects children and pregnant women and more elderly people … disproportionately compared to other populations.” 

In addition to asking the province to cut Ontario’s safety guideline in half, CELA and the Ontario Municipal Water Association want all lead service lines in the province mapped and removed by 2030. 

“The legislation and associated Ontario regulatory framework and standard for lead in drinking water are incomplete, outdated and inadequate to protect public health,” reads a May 7 statement from the two organizations. “The failure to review and revise the existing legislation and regulation is unnecessarily risking the health of people in Ontario.”

The nature of that health risk is more transparent to Ontarians than residents of other provinces. Ontario is the only province that makes in-depth, individual school and child-care centre water test results available free online. 

Across the country, such data is largely hidden. Some provinces, such as Nova Scotia and New Brunswick, provide limited testing results for certain years or municipalities. Others, including Alberta and Manitoba, don’t make their drinking water test results publicly accessible. 


About a third of the approximately 5,300 tests at the Ottawa-Carleton District School Board exceeded federal safety guidelines — the highest ratio for any school board in Ontario — between 2019 and 2023. 

At Cambridge Street Public School in Ottawa, 41 out of 44 tests returned with levels over the federal guideline, with four tests ranging between 105 ppb and 136 ppb. 

First Avenue Public School in Ottawa conducted 61 tests between 2019-2023, with more than 80 per cent showing lead levels over 5 ppb, two of which reached 1,500 ppb and 1,730 ppb.

The Ottawa-Carleton District School Board said in a statement that high test results at Cambridge Street and First Avenue public schools were due to resampling of problem fixtures, before rectifying the issues with provincially approved measures like flushing or adding lead filters.

Flushing is a method that requires water to be run through pipes for at least five minutes to remove any lead that may be left in standing water.

The high results from both schools were done when schools were closed due to provincial COVID regulations, reads the statement.

Leaside High School in Toronto, with about 1,000 students, tested for lead 74 times between 2019-2023, with just over 40 per cent of those tests exceeding the Health Canada guideline.

Of the nine fixtures that were above provincial standards, three are no longer in use for drinking, reads a statement from the Toronto District School Board (TDSB). Four others with high lead levels are flushed daily and two were returned to service after resampled tests.

“When there is an exceedance in the flushed sample, the fixture is taken out of service immediately to eliminate any further risk to occupants of the building,” the statement reads.

School boards and daycares in Peel, Dufferin, Hastings and Prince Edward County also had high numbers of tests above federal guidelines.

Nearly half of the 154 tests at Trenton High School, an hour west of Kingston in Hastings and Prince Edward County, surpassed 5 ppb between 2019 and 2023. The highest reading hit 71.9 ppb in September 2020. 

“A portion of the interior water service line was replaced in 2020 after the 2019 sampling results were received,” reads a statement from the Hastings and Prince Edward District School Board. The statement says the board also replaced exterior watermains and older drinking fountains in 2021.

For fixtures that continue to show elevated lead levels, the board says it flushes them to reduce lead contamination. But this only relates to tests that exceed the higher provincial guidelines. 

Between 2019 and 2023, 25 per cent of tests at Trenton High School exceeded provincial levels. But the number jumps to 45 per cent when evaluated against the federal guideline.


Assikinack Child Care in Barrie had among the highest rate of troubling tests among daycares with 12 of 16 tests above federal guidelines. The lead loads ranged from just over 5 ppb to a high of 217 ppb. 

After tests showed high levels of lead in 2020-2021, Ann Macdonald, vice-president of childcare programs at Upper Canada Child Care, the company that runs the daycare, said any taps testing with high lead were closed. Kids at the daycare have since been instructed to bring their own water, and bottled water is provided on-site.

YesKids Christian Childcare in Brantford had 16 out of 24 tests exceed Health Canada’s guideline. 

The majority of these positive tests were in 2019-2020. Larry Harrington, a spokesperson for YesKids Christian Childcare, said those tests were done to make sure the water quality was compliant before they opened in August 2020. He said YesKids installed filters and flushes the taps daily in order to meet provincial requirements.

On the discrepancy between Ontario’s guidelines and those of Health Canada, Harrington said “That’s not something I’ve been made aware of by our testing company.”

Learning Tree Academy Child Care Centre in Vaughan had two thirds of its tests reach levels over the federal guideline from 2021-2023. Of those tests, 15 were above 10 ppb, with one reaching 60 ppb in February 2022.

Aatish Jamal, owner of Learning Tree Academy, said their Vaughan location had high levels of lead due to the building being out of use after the previous daycare shut down. These tests were conducted before the Learning Tree Academy Child Care Centre opened.

The daycare brought its lead levels below provincial standards by flushing the pipes.

Aging infrastructure is a key factor in lead levels in schools because of legacy lead fixtures and pipes. The problem largely disappears in newer schools, the data show. 

St. Mary School in Fort Frances, Viola Desmond Public School in Milton and Sioux North High School in Sioux Lookout have all opened since 2019.

Not a single test conducted in the three schools over the past five years showed results above the federal guideline of 5 ppb. The highest result recorded was at Viola Desmond in 2019-2020, a reading of 3.1 ppb.But Viola Desmond has consistently tested at 0.5 ppb in the same year and every year after.

Given the health risks, even some people running schools and daycares with questionable test results think Ontario should tighten its lead safety guidelines.

“I’d like to see everybody get on the same page,” said Upper Canada Child Care’s Macdonald, who wasn’t aware of the difference between the provincial and federal lead safety guidelines. “No lead exposure is safe for children…. I think that it would be good for the provincial government to fall in line.”

Data Analysis: Andrew Bailey