December 2019 Board Meeting - Lead in Drinking Water Information Report

Meeting Document Type
Information Report
Lead in Drinking Water

Prepared By:

Phil Wong, Environmental Health Manager


December 19, 2019


Lead in Drinking Water


According to Health Canada, lead in drinking water should be kept as low as reasonably achievable. The most significant contribution of lead in drinking water is generally from lead service lines that supply drinking water to your home. The best approach to eliminate lead exposure is to remove and replace the full lead service line. Lead service lines have not been used for many years but older homes and buildings (pre-1948) may still have lead pipes and service lines. Lead solder and brass fittings/fixtures are also common sources of lead exposure. This report will highlight some of the key regulations and provide some clarification on how lead exceedances are handled in the province of Ontario.

Standards vs. Guidelines and Duty to Report

The Canadian guideline for lead in drinking water was lowered in June 2019 to 5ppb (0.005mg/L) or as low as reasonably achievable. In Ontario, the Drinking Water Quality Standards Reg. 169/03 and the Safe Drinking Water Act, 2002, have the maximum acceptable concentration (MAC) for lead in drinking water as 10ppb (0.010mg/L). All municipal drinking water systems and designated facilities are legally required to meet the 10ppb MAC. Under the Act, all drinking water system operators have a duty to report microbiological, chemical and radiological exceedances to their local public health unit and the Ministry of Environment, Conservation and Parks (MECP). The WECHU’s role is to give direction, in the event of an exceedance, on corrective action to eliminate/reduce any health effects.

Municipal Systems

The Drinking Water Systems Reg. 170/03 outlines the sampling protocol and testing requirements for municipal drinking water systems. The MECP regulates these systems and calls for the implementation of an extended lead testing-program. Targeted testing and sampling is conducted by municipal drinking water operators in each municipality, and any lead service lines are replaced when identified. Homeowners on municipal systems are encouraged to contact their local providers for options on lead sampling and other services. Homeowners are notified by the municipal drinking water operator and the health unit if lead is identified through operator sampling. 

Schools and Child Care Centres

Schools and child care centres are required to sample their water for lead as per Ontario Regulation 243/07: Schools, Private Schools and Child Care Centres. This regulation, recently amended in 2017, increased lead sampling requirements in these facilities. There is a requirement for annual sampling and testing of lead in drinking water to ensure lead levels are below the provincial Ontario Drinking Water Quality Standards Reg. 169/03. It also requires flushing of plumbing in schools to help reduce lead levels in drinking water. Flushing has been shown to reduce lead levels in water and is a recognized lead reduction strategy. Schools and child care centres have replaced service lines, decommissioned fountains, installed NSF POU filters and have bottle filling stations when lead exceedances have been identified. The regulation is enforced by the MECP as schools and child care centres are designated facilities, and the health unit takes a lead role to provide guidance on health related issues.

Private Water Supplies

Homeowners using private water supplies within Ontario can send water samples for lead testing to an accredited private laboratory from the MECP list. There is a cost associated with lead testing at a private laboratory. Private homeowners can submit water samples to the Public Health Ontario Laboratory for bacteriological testing (E. coli and total coliforms) and this service is free for all private drinking water systems.


Under the Ontario Public Health Standard’s Safe Drinking Water and Fluoride Monitoring Protocol, the health unit is mandated to provide 24/7 on-call support and response to all adverse drinking water events. Where water intended for human consumption may not be safe to consume, the health unit is required under the Health Protection Promotion Act to respond. The health unit initiates a response within 24 hours of receiving notification of any adverse event in the region. Boil Water and Drinking Water advisories, as well as legal orders to drinking water system operators, are issued regularly to prevent exposures to any microbiological, chemical or radiological exceedances. The health unit continues to work with municipal drinking water system operators, school boards and private well owners to provide awareness and education on safe drinking water.  

For more information on safe drinking water please visit the sites below:


Theresa Marentette

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