Guidance on controlling drinking-water corrosion

Summary#

The Government of Canada (through Health Canada) published a proposed guidance document on how to sample for and reduce corrosion in drinking water systems. The guidance focuses on reducing metals released by internal corrosion—especially lead—and is open for public comment from December 17, 2022 to February 15, 2023 (comments accepted within 60 days).

What it does#

• Explains how corrosion in drinking-water pipes and fittings can release metals such as lead.
• Provides sampling protocols and mitigation measures for water systems and buildings, including multi-dwelling residences, schools, daycares and office buildings.
• Emphasizes that the main contaminant of concern is lead and refers to Health Canada’s maximum acceptable concentration for lead of 0.005 mg/L (5 µg/L).
• Notes that corrosion control treatment can reduce lead at the tap but that supplying water through a lead service line may require removal of the full lead service line to meet the guideline.
• Limits its scope to internal distribution-system corrosion and to guidance-level actions; detailed operational plans and step-by-step removal projects are outside the document’s scope.
• Was developed with the Federal‑Provincial‑Territorial Committee on Drinking Water and is intended to complement the Canadian drinking water guideline technical document for lead.

Who's affected#

• Municipal and regional water utilities and the officials who manage them.
• Building owners, managers, school boards and employers responsible for multi-unit residential buildings, schools, daycares and offices.
• Residents and building occupants who get water through older plumbing or lead service lines.
• Health and environment officials who set or advise on local corrosion-control programs.
• If unclear: individual homeowners may be affected if their property has a lead service line, but the guidance is mainly aimed at responsible authorities.

Why it matters#

• Corrosion itself isn’t a direct health effect, but it can release contaminants—especially lead—that are harmful. Lead exposure in children is linked to lower IQ scores.
• The guidance gives practical sampling and corrective steps that can reduce people’s exposure to lead and other metals at the tap.
• For communities with lead service lines, the document makes clear that water treatment alone may not be enough; removing lead pipes is likely the most reliable long-term fix.
• The document is a draft for comment, so stakeholders can influence final advice during the public comment window (comments by email to water-eau@hc-sc.gc.ca).