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Reasonable Mitigation Obligations:
Involves Duty to Avoid Unnecessary Losses or Damages
Last Updated: July 01 2026
Question: How can a Paralegal in Ontario help me understand my duty to mitigate damages after I suffer a loss, and what reasonable steps should I take to avoid losing compensation?
Answer: The paralegal team at KLP Paralegal Services can help you understand the duty to mitigate, including the standard of taking reasonable steps to minimize avoidable losses in situations involving claims for breach, injury-related disputes, or employment-related disagreements across Ontario. In practice, we help you identify what losses may be considered avoidable, document the steps you took (or promptly took) to reduce harm, and explain what to expect about how mitigation is assessed, including that the other side generally has the burden to prove you did not take reasonable mitigation steps where mitigation is raised. If you need guidance on next steps and how to present mitigation in your matter, call (416) 570-6378 to book an initial conversation with KLP Paralegal Services serving clients throughout Ontario.
The Duty to Mitigate Including the Standard of Efforts to Do So
The law despises waste and the doctrine of mitigation, being the duty to mitigate, is the mechanism that imposes an obligation upon a harmed party to take reasonable steps to minimize or control avoidable losses. This principle applies in all matters of law including tort law, contract law, employment law, construction law, among various others matters.
The Law
The doctrine of mitigation was explained well whereas it was said in general by the Supreme Court in Southcott Estates Inc. v. Toronto Catholic District School Board, [2012] 2 S.C.R. 675, that:
[23] This Court in Asamera Oil Corp. v. Seal Oil & General Corp., 1978 CanLII 16 (SCC), [1979] 1 S.C.R. 633, cited (at pp. 660-61) with approval the statement of Viscount Haldane L.C. in British Westinghouse Electric and Manufacturing Co. v. Underground Electric Railways Company of London, Ltd., [1912] A.C. 673, at p. 689:
The fundamental basis is thus compensation for pecuniary loss naturally flowing from the breach; but this first principle is qualified by a second, which imposes on a plaintiff the duty of taking all reasonable steps to mitigate the loss consequent on the breach, and debars him from claiming any part of the damage which is due to his neglect to take such steps.
[24] In British Columbia v. Canadian Forest Products Ltd., 2004 SCC 38 (CanLII), [2004] 2 S.C.R. 74, at para. 176, this Court explained that “[l]osses that could reasonably have been avoided are, in effect, caused by the plaintiff’s inaction, rather than the defendant’s wrong.” As a general rule, a plaintiff will not be able to recover for those losses which he could have avoided by taking reasonable steps. Where it is alleged that the plaintiff has failed to mitigate, the burden of proof is on the defendant, who needs to prove both that the plaintiff has failed to make reasonable efforts to mitigate and that mitigation was possible (Red Deer College v. Michaels, 1975 CanLII 15 (SCC), [1976] 2 S.C.R. 324; Asamera; Evans v. Teamsters Local Union No. 31, 2008 SCC 20 (CanLII), [2008] 1 S.C.R. 661, at para. 30).
[25] On the other hand, a plaintiff who does take reasonable steps to mitigate loss may recover, as damages, the costs and expenses incurred in taking those reasonable steps, provided that the costs and expenses are reasonable and were truly incurred in mitigation of damages (see P. Bates, “Mitigation of Damages: A Matter of Commercial Common Sense” (1992), 13 Advocates’ Q. 273). The valuation of damages is therefore a balancing process: as the Federal Court of Appeal stated in Redpath Industries Ltd. v. Cisco (The), 1993 CanLII 3025 (FCA), [1994] 2 F.C. 279, at p. 302: “The Court must make sure that the victim is compensated for his loss; but it must at the same time make sure that the wrongdoer is not abused.” Mitigation is a doctrine based on fairness and common sense, which seeks to do justice between the parties in the particular circumstances of the case.
Accordingly, the duty to mitigate requires a harmed person to minimize the harm suffered. Failure to minimize the harm may, and likely will, reduce the sum that the wrongdoer will owe the harmed person in a determination of liability at a court Trial. As was explained above by the Supreme Court in the Southcott Estates case, where a failure to mitigate occurs, it is the failure of the Plaintiff to act reasonably to minimize the loss that caused a portion of the harm. Simply said, where the Defendant does something wrong resulting in harm to the Plaintiff, the Defendant is responsible only for the portion of the harm that arises directly due to the wrongdoing of the Defendant and where a portion of the harm occurs or accrues because the Plaintiff failed to minimize that harm, the Plaintiff is at blame for the portion of the harm.
Conclusion
A Plaintiff (or Defendant within a counterclaim) is required to mitigate by taking reasonable steps to keep losses at a minimum. Where a Plaintiff fails to reasonably take steps to minimize losses, it is the inaction of the Plaintiff rather than the wrongdoing of the Defendant that caused such losses. When a Defendant to a lawsuit seeks to argue failure to mitigate as a defence strategy, the Defendant must include such an allegation with the defence pleading documents and it is the Defendant that must prove that the Plaintiff had a reasonable opportunity to mitigate the losses and failed to do so. However, the Plaintiff is without a requirement to mitigate perfectly and must only take such steps that are reasonable at the time that the loss is occurring rather than as may appear possible at a later date through hindsight.
NOTE: A considerable amount of inquiries that include “lawyers near me” or “best lawyer in” frequently indicate a desire for prompt and competent legal support, rather than a specific job title. In Ontario, certified paralegals fall under the jurisdiction of the same Law Society that governs lawyers and are permitted to advocate for clients in certain litigation scenarios. Skills in advocacy, legal assessment, and procedural expertise are fundamental to this position. KLP Paralegal Services provides legal representation within its permitted mandate/scope, focusing on strategic alignment, evidence preparation, and compelling advocacy aimed at attaining swift and beneficial outcomes for clients.