Editor’s Note: This article has been translated and editorially updated for accuracy and to reflect current Canadian drinking-water guidance. Some historical information has been retained from the original publication for context.

When I first came to Canada, I was told by long-time residents that Canadian tap water was safe to drink directly from the tap. Public drinking fountains are common, and many people regularly drink tap water at home, at school, and in other public places.

But can we really be confident that tap water is always safe at the point where we drink it?

Reports of elevated lead levels in drinking-water outlets at Canadian schools and homes have raised important questions about the difference between the quality of treated municipal water and the quality of water that ultimately comes out of an individual tap.

Elevated Lead Levels Found at Some BC Schools

Historical testing in British Columbia found elevated lead levels at a number of drinking-water outlets in schools.

According to reporting by the Vancouver Sun, testing carried out across 60 school sites in BC during 2016 and 2017 involved approximately 10,000 drinking-water sources and 15,000 tests. Some samples contained lead concentrations above the drinking-water guideline in effect at the time.

The reported results varied considerably between locations. In some individual outlets, very high lead concentrations were detected. For example, testing reported at Walter Lee Elementary School in Richmond found one drinking-water sample with a lead concentration more than 300 times the applicable standard at the time. Other individual samples reported in Surrey also showed substantially elevated concentrations.

These historical results are important, but they should be understood in context. A high result from an individual fountain or tap does not necessarily mean that the municipal water supply itself contains the same concentration of lead. Lead can enter water after it leaves the treatment plant through plumbing, fixtures, solder, and service lines.

Health Canada identifies plumbing and distribution-system components as important sources of lead in drinking water, particularly in older buildings and neighbourhoods.

Lead Has Also Been Found in Ontario Schools and Homes

Similar concerns have been reported in Ontario.

Historical testing identified elevated lead levels in drinking-water samples from schools and child-care facilities, including schools in the York Region area. These findings illustrate why the plumbing within a particular building can be an important factor when evaluating drinking-water quality.

Again, the results from individual outlets should not automatically be interpreted as evidence that an entire municipal water supply is contaminated. Lead concentrations can vary significantly between different taps and locations within the same building.

Lead in Older Toronto Homes

Toronto has also dealt with lead service lines and other older plumbing components.

The City of Toronto states that water produced at its drinking-water treatment plants does not contain lead. Lead can instead enter drinking water through older plumbing, including lead water service pipes, older solder, and lead-containing brass fixtures.

Lead service pipes were commonly used in Toronto homes built before the mid-1950s. The City estimates that just under 16,000 City-owned lead water service pipes remain among approximately 437,000 residential customers.

In Toronto, the water service pipe is divided between the City and the property owner. The City-owned portion generally runs from the watermain to the property line, while the portion from the property line into the home is privately owned.

This is an important distinction: the presence of a lead service line or other lead-containing plumbing does not necessarily mean that the water entering the property from the municipal system contains elevated lead. Rather, lead can be introduced into the water as it comes into contact with those plumbing materials.

Why Can Lead Enter Drinking Water?

Lead is not normally added to drinking water. It can enter water when it comes into contact with lead-containing plumbing materials.

Historically, lead was widely used in water service lines, solder and plumbing fittings. Corrosion can cause lead to leach from these materials into the water. Water chemistry, plumbing materials, and the length of time water remains in the plumbing can all influence lead concentrations at the tap.

This is why water quality can vary from one building or tap to another, even when the buildings receive water from the same municipal system.

What Is the Current Canadian Guideline for Lead?

Health Canada’s current maximum acceptable concentration (MAC) for total lead in drinking water is 5 µg/L (5 parts per billion), based on an appropriate sample collected at the tap. This guideline replaced the previous 10 µg/L value in 2019.

Health Canada also recommends keeping lead concentrations as low as reasonably achievable (ALARA) because current science has not identified a level of lead exposure below which adverse health effects can be ruled out.

The guideline should not be interpreted as meaning that Canadian tap water generally contains 5 µg/L of lead. Actual concentrations depend on the source water, distribution system, plumbing materials, and conditions at the individual tap.

Long-Term Lead Exposure Can Affect Health

Lead is a toxic metal and exposure can affect the nervous system and other parts of the body.

Children are particularly vulnerable because their brains and nervous systems are still developing. Health Canada identifies adverse cognitive and behavioural effects in children as important health concerns associated with lead exposure. Effects associated with lead exposure in adults include increased blood pressure and kidney dysfunction.

Lead exposure does not necessarily produce obvious symptoms. This is one reason that testing can be useful when there is a known or suspected source of lead in a home’s plumbing.

Severe lead poisoning can cause serious illness and can be life-threatening. However, this should not be interpreted to mean that ordinary Canadian tap water is generally toxic or that drinking municipal water normally causes lead poisoning.

What Can You Do to Reduce Exposure to Lead?

If you are concerned about lead in your drinking water, there are several practical steps that can help reduce exposure.

Test Your Water

Testing is the most reliable way to determine whether lead is present at a particular tap.

If your home or building is older, if you suspect that it has lead plumbing, or if you have another reason to be concerned, contact your municipality or a qualified laboratory about appropriate drinking-water testing.

Testing can also help determine whether additional treatment is appropriate.

Use Cold Water for Drinking and Cooking

Use cold tap water for drinking, cooking, and preparing infant formula.

Hot water can increase the leaching of lead and other metals from plumbing. If hot water is needed for cooking or drinking, use cold water and heat it separately.

Flush Stagnant Water

When water has been sitting in household plumbing for an extended period, flushing the cold-water tap can help reduce water that has had prolonged contact with plumbing materials.

The appropriate flushing procedure depends on the plumbing system and local guidance.

Address the Source of the Lead

If lead is confirmed, addressing the source is important.

Where a lead service line is present, replacing the complete service line is considered the most effective and permanent way to reduce lead from that source. Other plumbing components, such as faucets, fittings, and solder, may also contribute to elevated lead concentrations.

Does Boiling Water Remove Lead?

No. Boiling water does not remove lead.

Boiling can be useful for controlling certain microorganisms when recommended during a boil-water advisory, but it should not be relied upon to remove lead from drinking water.

If lead is the concern, the appropriate approach is to identify and address the source and, where necessary, use a treatment method specifically designed and certified for lead reduction.

Can Water Filtration Reduce Lead?

Certain drinking-water treatment systems can reduce lead concentrations.

The appropriate treatment method depends on the water and the source of the lead. Treatment technologies may include filtration, adsorption, reverse osmosis, and other approaches.

When selecting a treatment device, look for a third-party certified product with a specific lead-reduction claim rather than assuming that every filter removes lead.

Applicable standards can include NSF/ANSI 53 for drinking-water treatment systems with lead-reduction claims and NSF/ANSI 58 for reverse-osmosis drinking-water treatment systems. Certification should be checked for the specific product and model being considered.

WQA’s certification programs provide third-party certification of drinking-water treatment products to applicable industry standards. The important consideration is that the product has been independently tested and certified for the contaminant-reduction claim you need.

Should You Be Concerned About Your Drinking Water?

Canada’s drinking water is generally of high quality, and municipal water is treated and monitored according to requirements established by the responsible jurisdiction.

At the same time, the water that leaves a treatment plant can be different from the water that comes out of an individual household tap. Lead can enter drinking water from plumbing and service-line materials, particularly in older homes and buildings.

For this reason, if you live in an older home, are unsure about your plumbing, or have a specific reason to be concerned about lead, testing your water can provide useful information.

If elevated lead is found, the appropriate response is to identify the source, reduce exposure, and consider a treatment device that has been independently certified for lead reduction when appropriate.

The Bottom Line

Canadian tap water is generally treated and monitored to provide safe drinking water, but that does not mean that every tap will necessarily have the same water quality.

Lead can enter drinking water through older service lines, solder, faucets, fittings, and other plumbing components. Because lead exposure can be particularly harmful to developing children, it is important to keep exposure as low as reasonably achievable.

If you are concerned about lead in your drinking water, test first, identify the source, and choose an appropriately certified treatment solution if treatment is needed.

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