Former senior City of Toronto engineer Liza Ballantyne posed an intriguing question to the city’s associate medical officer of health in December 2017: When the city has residents test their tap water for lead, why does it tell them first to run or “flush” their taps for five minutes?

“By flushing for five minutes we may not get a true representation of the residents’ lead exposure,” Ballantyne wrote in an email to the medical officer, Howard Shapiro at Toronto Public Health.

A more realistic testing method would “provide homeowners with a less conservative lead value to encourage them to replace their lead pipes,” she wrote in another email to colleagues.

The consensus in the scientific community — from academics to the federal government —agrees with her.

Flushing tap water immediately before collecting samples produces misleadingly low results that fail to alert residents and municipalities to real lead levels and the accompanying health risks. These include learning disabilities, memory loss, brain damage, high blood pressure, heart disease and renal dysfunction, as well as a greater number of miscarriages and preterm births.

In children, lead levels can affect brain development and have been linked to ADHD, lower IQs and academic performance, behavioural problems and delayed puberty.

Health Canada recommends that tap water sit for 30 minutes before sampling; in the U.S., the standing time for lead test samples is six hours.

“It must be recognized that many provinces and territories currently assess compliance for lead based on a flushed sample, which is not representative of exposure,” reads Health Canada’s lead testing guideline released in March 2019.

For mandatory lead test results submitted to the province, the City of Toronto follows the provincial requirement of testing water that has been standing for 30 minutes. But far more tests each year are conducted under the city’s non-regulated program in which residents collect samples from their taps and submit them to Toronto Public Health for analysis.

The testing kit from Toronto Public Health reads: “Let the water at the kitchen tap run either for five minutes or until at least one minute after the temperature of the water is consistently cold.”

Switching to the 30-minute standing protocol would bring the results in line with provincial testing protocols and “facilitate the comparison of the two sets of data,” Ballantyne wrote in a November 2017 email.

Associate medical officer Shapiro agreed with Ballantyne about Toronto’s testing program, according to emails obtained through freedom of information requests.

“While I understand that it is a nice service for residents I do feel it can be misleading,” Shapiro wrote to Ballantyne last year. “I think it’s great to have someone revisit this and ask if we can do it in a better way. Trying to minimize people’s exposure to lead is definitely a worthy health issue.”

While changing the protocol would require more public education and messaging, Shapiro wrote, “it is not a bad thing if more samples come back high and more people have a replacement of their lead service.”

But Shapiro wrote to Ballantyne, “Right now, there is not much desire to take this on.”

A 2016 poll of Torontonians, commissioned by Toronto Public Health, asked homeowners who had conducted lead water tests why they hadn’t replaced their lead service lines. Half of respondents said the primary reason was that their “lead test results came back safe.”

Ballantyne, who is now manager of water treatment with Peel Region, declined an interview, writing in an email “I do not feel comfortable speaking about the subject matter given that I am no longer employed by the City.”

In a recent interview, Shapiro stood by his comments and his concerns about the flushed test results.

“I feel it’s (Toronto Water’s) program and they get to decide what to do with it,” he said. “The result potentially could be misleading or falsely reassuring.”

Asked why the testing has not changed, Shapiro said “That’s a good question.”

William Fernandes, director of water treatment and supply at Toronto Water, said the agency will “take it up with Toronto Public Health and see how to make what we have better...We have always done things jointly with Toronto Public Health.”

The city has processed 8,500 tests using the flushed protocol since 2014 with about six per cent exceeding the federal lead safety guideline of 5 parts per billion.

Each test costs about $50 to administer. Last year, the bill came to about $49,000.

These tests create a false sense of security, said Marc Edwards, a professor of environmental and civil engineering at Virginia Tech who helped expose the water crisis in Flint, Mich., in 2015.

“Are you trying to honestly find a problem and give consumers the answer that they need to protect themselves and their families from the best-known neurotoxin? Or, are you trying to cover up a problem and perpetuate harm?”

Dr. Aaron Thompson, a Toronto toxicologist and lead specialist, said: “If people don’t usually flush their water, then you should test the way they normally use it.”

Yanna Lambrinidou, a U.S. researcher on lead in water at Virginia Tech, called Toronto’s water testing instructions “highly problematic.”

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“It’s safe to say the results that come out of this type of testing grossly underestimate the levels of lead that are flowing from people’s taps,” she said. “What it looks like we are facing here is either institutional ignorance...or we are looking at willful manipulation of a testing regime to minimize the chances of finding the full extent of the problem.”

The contrast between flushing and standing methods can be found in results from Halifax. From 2012 to 2017, 747 lead tests were “first litre” standing tests, and another 747 were of water that had been flushed. The failure rate for standing tests was more than 150 per cent higher.

In Quebec, municipalities have historically flushed taps for five minutes before gathering samples, a method Michèle Prévost, a professor of engineering at Polytechnique Montreal and one of Canada’s leading experts on lead in water, calls “ethically unacceptable.”

For more than 10 years, Prévost chaired a committee on drinking water that advised the Quebec government. She says she presented strong evidence in 2012 that Quebec’s flushing method is scientifically flawed and should be replaced with sampling from standing water.

When the ministry continued with this method, Prévost had enough and quit.

“I insisted the utilities to go along with this, to go to the new sampling, and they back-tracked and did nothing,” she said. “When the government refused to consider it, I thought my energy would be better spent doing work with people who actually act upon data and evidence. ”

Two weeks ago, after being presented with the findings from this investigation, Quebec officials promised a broad overhaul of the province’s testing methods including scrapping the five-minute flush test.

“It doesn’t seem to me like it should be this complicated to do the [right] test,” Quebec Premier Francois Legault said. “So [Quebec Health Minister] Danielle McCann will ensure that municipalities everywhere will do tests correctly… as Health Canada recommends.”

Flushing is illegal in the United States. In 2016, two Michigan state water officials were charged in connection with the Flint crisis for, among other things, instructing residents to flush before testing. The charges, which carry a penalty of one year in prison and/or $5,000 (USD) for each day of violation, were dismissed as part of a plea deal.

In 2015, Miguel Del Toral, a manager with the U.S. Environmental Protection Agency’s water division, warned that taps in Flint were being flushed before testing. “(Flushing) has been shown to result in the minimization of lead capture and significant underestimation of lead levels in the drinking water,” he wrote. Del Toral said that the results “may result in residents not taking necessary precautions to protect their families.”

Like municipal water agencies across Canada, Toronto officials advise residents of older homes to remove lead plumbing or flush their taps before consuming or cooking with tap water.

“That advice (to flush taps for five minutes) has been given for decades but a lot of people didn’t know. It wasn’t well publicized,” said Toronto Water general manager Lou Di Gironimo.

Even if residents with lead pipes flushed their taps every morning, the risk to health isn’t removed “because if you wait an hour (after flushing), you’re back up almost to where you were before,” said Prevost.

Bruce Lanphear, a Simon Fraser University researcher on health effects of lead, said maintaining safe lead levels in a home with lead pipes could mean flushing five or six times a day for a couple of minutes each time. That amounts to major waste and expense few people will undertake.

“How much water does that add to your water bill and to the overconsumption of water?” he said. “Have you ever stood for two minutes and watched your water tap? People won’t do it.”

If the Canadians living in more than 6 million pre-1975 homes and apartment buildings were to flush their taps for five minutes twice a day — once in the morning and once after getting home from work — it would send approximately 115 billion litres of water down the drain each year (based on an average faucet flow rate). In a best-case scenario of low-flow taps, this number is closer to 42 billion. In the worst, it’s as high as 186 billion litres of water per year.

“It is a very large volume,” said Dr. Evan Davies, a University of Alberta civil engineer who reviewed the investigation’s analysis.

“What it really comes down to is who is responsible for the lead service lines. If that is a municipal responsibility, then asking residents to essentially be responsible for their own health is more problematic.”

The water that would be flushed down the drain represents about 3.6 per cent of the country’s total residential water usage (based on Stats Canada data from 2013). That’s enough to ice 2.4 million hockey rinks each year — equivalent to every rink in the world 141 times over.

In Toronto alone, a flushing regimen would cost $2.2 million each year, all paid by Toronto Water customers — homeowners, businesses and renters.

“These numbers are incredibly high,” said Darko Joksimovic, a civil engineer and professor at Ryerson University who also reviewed the investigation’s analysis.