Status: Archived historical article
Last editorial review: October 2026

Water quality experts believe that reports indicating Toronto’s drinking water poses health risks—with 13% of households having tap water that exceeds safety standards—are not alarmist. This is a legacy issue stemming from the fact that some of the city’s underground drinking water pipes are made of the heavy metal lead, which has led to drinking water safety concerns over the years. Certified water quality expert Zhao Wenjie (pictured) points out that the city government is already seeking solutions. Under the current circumstances, the simplest and most effective method is to run the tap for about 5 minutes every morning before drinking the first glass of cold water. To reduce the risks associated with household tap water, residents may consider installing water filters or water softening systems. Daily Lead Ingestion Can Cause Blood Poisoning

Zhao Wenjie stated that Toronto’s household tap water has long posed numerous health risks, though these have only recently come to light. From before the 1950s through the early 1990s, the city’s underground drinking water pipes—part of its infrastructure—were primarily made of lead, which was used to transport drinking water to every household’s faucets. The city government used lead pipes because they are rigid, easy to solder, and resistant to damage. However, lead is a toxic heavy metal that, once accumulated in the human body, cannot be excreted. Zhao Wenjie explained that after decades of use, lead pipes naturally flake or leave behind lead residue. As this water flows through household plumbing, it inevitably becomes contaminated with lead. The situation may be even more severe in older neighborhoods, where residents who drink tap water are effectively ingesting lead on a daily basis. Over time, this can harm health; in severe cases, it may lead to kidney disease, blood poisoning, and damage to the central nervous system, while children may develop conditions such as attention deficit hyperactivity disorder (ADHD). For this reason, since the 1990s, the city government has banned the use of lead pipes in underground drinking water systems, replacing them with other materials such as plastic pipes. In fact, many city governments became aware of the drinking water issue more than a decade ago and encouraged residents to install water filters compliant with the National Sanitation Foundation’s (NSF) standards (NSF 53) or purified water (softened water) systems (NSF 58) on their faucets. This is because softened water effectively removes lead through ion exchange, thereby protecting public health. Installing Water Filters Reduces Risk

Zhao Wenjie noted that if a water filter or filtration system is not installed, a temporary solution is to let the tap run for about 5 minutes every morning before drinking the first glass of water (not hot water). The purpose is to flush out sediment, toxic substances, or bacteria that may have accumulated in the water pipes or faucets. If the city government is repairing or replacing underground water pipes, it is even more important to let the water run for at least 15 minutes before drinking the first glass of water. In addition, residents should regularly rinse the built-in filters in their home faucets to reduce risks.

2026 Editorial Update

This article is preserved in its original form. We have added this note to provide readers with some additional context based on current information.

Toronto continues to address legacy lead service lines and plumbing in older properties. The City has taken significant steps to reduce lead exposure, including corrosion control and ongoing replacement of lead water services. The 13% figure mentioned in this article refers to historical household testing conducted between 2008 and 2014 and should be understood in that context, rather than as a current estimate of Toronto households.

The article’s recommendation to run the cold tap for about five minutes before drinking remains a practical precaution consistent with Toronto’s current guidance when water has been sitting for several hours. Residents concerned about lead can also consider having their water tested and using a filter specifically certified for lead reduction.

The original article’s broader message remains relevant: lead is a toxic substance, and older plumbing can be a source of lead in household drinking water. The purpose of this update is simply to give readers additional context about Toronto’s ongoing efforts to reduce lead exposure and the current understanding of the issue.