Overview
Every March, Waterloo’s University district turns into a sea of green as thousands gather for unsanctioned St. Patrick’s Day street parties. These unlicensed gatherings, or “Nuisance Parties,” have resulted in property damage, blocked roads, overwhelmed emergency services, and concerned taxpayers for the City of Waterloo. Despite annual increases in bylaw enforcement and ticketing, these Nuisance Parties continue to escalate. This year, Waterloo sought a new prevention tool: a quia timet injunction.
In the recent decision of The Corporation of the City of Waterloo v Persons Unknown, 2025 ONSC 1572 (“Waterloo v Persons Unknown”), the Ontario Superior Court (“ONSC”) granted an interlocutory statutory injunction under section 440 of Ontario’s Municipal Act, 2001 and an interlocutory quia timet injunction against “persons unknown.”[1] The injunctions were intended to support Waterloo in taking proactive legal measures to prevent Nuisance Parties.
Section 440 Injunction and the Modified Legal Test
Justice Gibson’s decision to grant the section 440 injunction hinged on a modified legal test. The standard common law three-part test for interlocutory injunctions requires the moving party to demonstrate: (1) a serious issue to be tried, (2) that irreparable harm will result if the injunction is not granted, and (3) the balance of convenience favours granting the injunction.[2]
When a municipality seeks an injunction under section 440, it only needs to satisfy the first branch of the test, that there is a serious issue to be tried.[3] This is because municipalities are presumed to act in the public interest, and a breach of law constitutes irreparable harm to that interest.[4]
In this decision, though, the ONSC applied a modified version of the section 440 test, requiring a higher threshold than that of just a serious issue. Namely, the municipality had to establish a strong prima facie case.[5] As a result, this injunction offered a tool for obtaining swift, court-ordered relief in situations where urgent action is needed to prevent harm to the public.
The Decision on the Quia Timet Injunction
A quia timet injunction is a preventative remedy used to restrain wrongful acts that are imminent or threatened but have not yet occurred.[6] Justice Gibson applied the traditional three-part common law test from RJR-MacDonald Inc v Canada (Attorney General) [1994] 1 SCR 311 and found that the injunction was warranted based on the following:
- Strong Prima Facie Case of an Anticipated Bylaw Breach: The ONSC accepted Waterloo’s compelling evidence of consistent bylaw infractions and related public safety concerns tied to previous gatherings. In addition, anonymous social media accounts were actively promoting similar events planned for 2025, indicating that a nuisance was imminent.[7]
- High Probability of Irreparable Harm: The ONSC found that Waterloo would likely suffer significant, non-compensable harm if the gatherings proceeded. These harms included substantial financial costs and the strain on first-responder resources.[8]
- Balance of Convenience Favours Waterloo: The potential harm to Waterloo outweighed any prejudice to the unnamed Respondents, particularly since the Respondents would not face any legitimate deprivation from the injunction being granted.[9]
In addition to evidence of past street events which involved severe overcrowding, property damage, public intoxication, and total municipal costs exceeding $1,000,000, Waterloo supported its motion with letters from local post-secondary institutions, hospitals, and regional public service leaders.[10] Justice Gibson found these submissions compelling enough to form the basis of his decision.
Charter Considerations
The ONSC also addressed the Respondents’ rights to freedom of assembly under s.2 of the Canadian Charter of Rights and Freedoms.[11] Justice Gibson emphasized that while peaceful assembly is protected, it does not extend to gatherings that threaten public safety or disregard lawful municipal enactments.[12] In other words, Justice Gibson was clear: the Charter does not give anyone the right to endanger public safety or ignore municipal laws.
Implications of the Injunctions
With the injunctions in effect, Waterloo police and bylaw officers were empowered to charge party hosts, planners, or attendees with violating a court order. Because breaching a court order carries more severe penalties than a typical ticket, this would better support the goal of deterring Nuisance Parties. The injunctions were limited in scope, applying only to specific geographic areas for a specific number of days surrounding the anticipated event.[13]
Key Takeaways and Future Considerations
The Waterloo v Persons Unknown decision illustrates that with the proper evidence and community backing, municipalities may use robust legal tools to protect their residents and public spaces. What remains to be seen is whether there is an appetite to enforce such injunctions. While the decision marks a significant development in how cities can respond to unsanctioned parties and related threats, Waterloo still experienced a St. Patrick’s Day Nuisance Party this year, with thousands of people in attendance and multiple arrests and charges laid. Balancing a vibrant community life with public safety remains a challenge. University towns such as Guelph, Kingston, London, Ottawa, Hamilton and other municipalities facing disruptive street parties may consider Waterloo’s precautionary approach as a guiding precedent and as one more tool to help contain these events.
[1] The Corporation of the City of Waterloo v Persons Unknown, 2025 ONSC 1572 at para 2.
[2] Ibid at para 27.
[3] Ibid at para 28.
[4] Ibid.
[5] Ibid at para 29.
[6] Ibid at para 37.
[7] Ibid at para 42.
[8] Ibid at para 43.
[9] Ibid at para 45.
[10] Ibid at paras 7, 8 and 17.
[11] Ibid at para 47.
[12] Ibid.
[13] Ibid at para 5.
The author would like to thank Derren Forman, Summer Student-at-Law, for his assistance with this article.