City of Thunder Bay Leaking Pipes Class Action

Roy O’Connor LLP has issued a proposed class action lawsuit against the City of Thunder Bay for damage alleged to be caused to pipes and plumbing systems following the City’s introduction of sodium hydroxide into the municipal water supply. The damage alleged includes what are described as “pinhole leaks” in the plumbing, the significant costs to repair the leaks, and the resulting damage from the leaks.

The proposed class action seeks compensation totaling $350,000,000 to cover the thousand or tens of thousands of residents, businesses and other operations whose pipes and plumbing systems were damaged or, are at risk of damage and failure, by the City’s introduction of sodium hydroxide into the water supply years ago. Following complaints and concerns being raised, the City discontinued the use of sodium hydroxide earlier this year.

The Plaintiff’s statement of claim alleges that, among other things, the City owed legal duties to the proposed class members (including individuals, businesses and other organizations supplied with water from the City) to ensure that the water supply did not unnecessarily corrode their pipes and plumbing systems. The statement of claim alleges that the City breached those duties through the introduction and use of sodium hydroxide into the water supply. The statement of claim further alleges that the City had more reasonable, prudent and appropriate alternatives (other than the introduction of sodium hydroxide) that were readily available to address any concerns that the City had about the potential leaching of lead in plumbing systems in a subset of local properties. The Plaintiff’s allegations have yet to be proven in Court.

Next Steps

The Plaintiff served her motion record in support of certification on February 18, 2022. The City of Thunder Bay is served its responding record in August, 2022.

The hearing of the certification motion proceeded via Zoom on June 14, 2023 before the Honourable Justice Paul Perell of the Ontario Superior Court of Justice. Justice Perell reserved his decision.

In Reasons for Decision released on July 6, 2023 Justice Perell certified this action as a class proceeding.

In very general terms, this decision means that the case will move ahead on behalf of the Class and can proceed to a future determination by a judge on the questions whether the City breached a duty owed to the class and, if so, whether the City caused or contributed to losses sustained by the Class. For clarity, and as set out above, this decision did not make any determinations on the merits of those questions. We also note that His Honour did not certify another additional claim in what is known in legal terms as ‘nuisance.’ The nuisance claim was not permitted to proceed in part because His Honour found that the City of Thunder Bay is immune from these claims in nuisance for the escape of water pursuant to s. 449 of the Municipal Act.

Please note that this is a brief and unofficial update on the status of this class action. An official, court-approved notice of certification will be provided to Class Members at some point in the future, summarizing, among other, the Class Members’ rights in this action arising from certification and instructions on how to exclude themselves (i.e. opt-out) from this proceeding.

Additional updates will be posted on this site as the case develops.

Register For More Information

If you believe that you may be a class member in this proceeding and wish to receive information from time to time about the status of the lawsuit, you may request such information by filling in the form found at: The Registration Page

More Information

For more information please contact James Katsuras at:


Phone: 416-362-1989
Toll Free: 1-888-303-5033

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