What Type of Conduct Can Constitute As the Tort of Nuisance?
Tortious Nuisance May Occur When Interference In the Use or Enjoyment of Property Is Substantial and Unreasonable Taking Into Consideration the Character of the Neighbourhood, Among Other Factors. Noise, Smoke, Smell, Lights, Issues With Tree Roots, Harassment, Among Other Things, May Be a Nuisance.
Understanding What Constitutes As Tortious Nuisance By Unreasonable Interference In Use or Enjoyment of Property
The law of nuisance is often classed as falling within the field of tort law; however, some legal academics view nuisance as independent of tort law. Regardless, nuisance is historic and has broad applications in law. Interestingly, while nuisance may involve wrongdoing, intentional or negligent, as discussed below, nuisance may also arise from conduct that is fully lawful and absent of any illicit conduct or untoward purpose yet results in an unreasonable interference in the use or enjoyment of the property of others. As a very flexible tort, nuisance may apply to many situations; and accordingly, the tort of nuisance is frequently relied upon.
Definition of Nuisance
Defining nuisance law, and the confines of what constitutes nuisance, is often very challenging. Doing so may even be challenging for the judiciary. Various cases, including Desando v. Canadian Transit Company, 2018 ONSC 1859, Milne v. Saltspring Island Rod and Gun Club, 2014 BCSC 1088, Antrim Truck Centre Ltd. v. Ontario (Transportation),  1 S.C.R. 594, St. Lawrence Cement v. Barrette,  3 S.C.R. 392, and St. Pierre v. Ontario (Minister of Transportation & Communications),  1 S.C.R. 906, all attempt to encapsulate the essence of the tort of nuisance, including what constitiutes as a substantial and unreasonable interference, wherein these cases it was respectively stated:
 In the Law of Torts in Canada, 3d ed (Toronto: Carswell, 2010) by Gerald H.L. Fridman, Professor Fridman outlines the challenges courts are presented when “[t]he impossibility of providing a definition of nuisance for legal purposes has frequently been stated. Nuisance is a vague doctrine, very difficult to define accurately.”
 In Canadian Tort Law: Cases, Notes and Materials, 14th ed (Markham: LexisNexis Canada, 2014) by The Hon. Allen M. Linden, Lewis N. Klar, and Bruce Feldthusen, the authors open with an encapsulation:
Nuisance is a field of liability that describes a type of harm suffered by the plaintiff, rather than a type of objectionable conduct engaged in by the defendant. Public nuisance deals with the use and enjoyment of the general public’s right to use and enjoy public areas such as rights of way. A private nuisance is a substantial interference with an occupier’s use and enjoyment of land, an interference which is unreasonable in the circumstances. The “substantial” requirement eliminates consideration of trivial interferences. The “unreasonable” requirement is determined by a balancing exercise that considers factors such as the severity of the interference, the duration, the character of the neighbourhood, the sensitivity of the plaintiff and the utility of the defendant’s conduct. . . . In the absence of physical damage, the so-called loss of amenity cases, the balancing exercise may be detailed and difficult.
 The legal principles of nuisance are well established and uncontroversial. Nuisance is the unreasonable interference with a person's enjoyment of his or her land or physical damage to that land. Some judgments and texts refer to a requirement of the interference being serious, but logically that can be subsumed in the "unreasonable" analysis.
 The difficulty in nuisance cases is applying the concept of reasonableness. Determining whether something is a nuisance always involves balancing the interests between the parties. The principle is stated succinctly in Clerk & Lindsell on Torts, 20th ed. (London: Thomson Reuters (Legal), 2010) at para. 20–10:
Question of degree In nuisance of the third kind, "the personal inconvenience and interference with one's enjoyment, one's quiet, one's personal freedom, anything that discomposes or injuriously affects the senses or the nerves", there is no absolute standard to be applied. It is always a question of degree whether the interference with comfort or convenience is sufficiently serious to constitute a nuisance. The acts complained of as constituting the nuisance, such as noise, smells or vibration, will usually be lawful acts which only become wrongful from the circumstances under which they are performed, such as the time, place, extent or the manner of performance. In organised society everyone must put up with a certain amount of discomfort and annoyance caused by the legitimate activities of his neighbours. Ordinary domestic use of premises therefore cannot constitute a nuisance, even though interference with the enjoyment of neighbouring premises is caused, if that interference results solely from construction defects for which the defendant is not responsible. In attempting to fix the general standard of tolerance the vague maxim sic utere tuo ut alienum non laedas has been constantly invoked. But the maxim is of no use in deciding what is the permissible limit in inconvenience and annoyance between neighbours, and the courts in deciding whether an interference can amount to an actionable nuisance have to strike a balance between the right of the defendant to use his property for his own lawful enjoyment and the right of the claimant to the undisturbed enjoyment of his property. No precise or universal formula is possible, but a useful test is what is reasonable according to ordinary usages of mankind living in a particular society.
 The main question here is how reasonableness should be assessed when the activity causing the interference is carried out by a public authority for the greater public good. As in other private nuisance cases, the reasonableness of the interference must be assessed in light of all of the relevant circumstances. The focus of that balancing exercise, however, is on whether the interference is such that it would be unreasonable in all of the circumstances to require the claimant to suffer it without compensation.
 In the traditional law of private nuisance, the courts assess, in broad terms, whether the interference is unreasonable by balancing the gravity of the harm against the utility of the defendant’s conduct in all of the circumstances: see, e.g., A. M. Linden and B. Feldthusen, Canadian Tort Law (9th ed. 2011), at p. 580. The Divisional Court and the Court of Appeal identified several factors that have often been referred to in assessing whether a substantial interference is also unreasonable. In relation to the gravity of the harm, the courts have considered factors such as the severity of the interference, the character of the neighbourhood and the sensitivity of the plaintiff: see, e.g., Tock, at p. 1191. The frequency and duration of an interference may also be relevant in some cases: Royal Anne Hotel, at pp. 760-61. A number of other factors, which I will turn to shortly, are relevant to consideration of the utility of the defendant’s conduct. The point for now is that these factors are not a checklist; they are simply “[a]mong the criteria employed by the courts in delimiting the ambit of the tort of nuisance”: Tock, at p. 1191; J. P. S. McLaren, “Nuisance in Canada”, in A. M. Linden, ed., Studies In Canadian Tort Law (1968), 320, at pp. 346-47. Courts and tribunals are not bound to, or limited by, any specific list of factors. Rather, they should consider the substance of the balancing exercise in light of the factors relevant in the particular case.
 The way in which the utility of the defendant’s conduct should be taken into account in the reasonableness analysis is particularly important in this case and would benefit from some explanation.
 The first point is that there is a distinction between the utility of the conduct, which focuses on its purpose, such as construction of a highway, and the nature of the defendant’s conduct, which focuses on how that purpose is carried out. Generally, the focus in nuisance is on whether the interference suffered by the claimant is unreasonable, not on whether the nature of the defendant’s conduct is unreasonable. This point was made by the court in Jesperson’s Brake & Muffler Ltd. v. Chilliwack (District) (1994), 1994 CanLII 1662 (BC CA), 88 B.C.L.R. (2d) 230 (C.A.). In that case, the construction of an overpass resulted in a 40 percent drop in the market value of the claimant’s lands. The statutory authority argued that the claimant had to establish (and had failed to do so) that the statutory authority had used its land unreasonably. The Court of Appeal correctly rejected that contention. The focus of the reasonableness analysis in private nuisance is on the character and extent of the interference with the claimant’s land; the burden on the claimant is to show that the interference is substantial and unreasonable, not to show that the defendant’s use of its own land is unreasonable.
 The nature of the defendant’s conduct is not, however, an irrelevant consideration. Where the conduct is either malicious or careless, that will be a significant factor in the reasonableness analysis: see, e.g., Linden and Feldthusen, at pp. 590-91; Fleming, at s. 21.110; Murphy and Witting, at p. 439. Moreover, where the defendant can establish that his or her conduct was reasonable, that can be a relevant consideration, particularly in cases where a claim is brought against a public authority. A finding of reasonable conduct will not, however, necessarily preclude a finding of liability. The editors of Fleming’s The Law of Torts put this point well at s. 21.120:
. . . unreasonableness in nuisance relates primarily to the character and extent of the harm caused rather than that threatened. . . . [T]he “duty” not to expose one’s neighbours to a nuisance is not necessarily discharged by exercising reasonable care or even all possible care. In that sense, therefore, liability is strict. At the same time, evidence that the defendant has taken all possible precaution to avoid harm is not immaterial, because it has a bearing on whether he subjected the plaintiff to an unreasonable interference, and is decisive in those cases where the offensive activity is carried on under statutory authority. . . . [I]n nuisance it is up to the defendant to exculpate himself, once a prima facie infringement has been established, for example, by proving that his own use was “natural” and not unreasonable.
 At common law, nuisance is a field of liability that focuses on the harm suffered rather than on prohibited conduct (A. M. Linden and B. Feldthusen, Canadian Tort Law (8th ed. 2006), at p. 559; L. N. Klar, Tort Law (2nd ed. 1996), at p. 535). Nuisance is defined as unreasonable interference with the use of land (Linden and Feldthusen, at p. 559; Klar, at p. 535). Whether the interference results from intentional, negligent or non‑faulty conduct is of no consequence provided that the harm can be characterized as a nuisance (Linden and Feldthusen, at p. 559). The interference must be intolerable to an ordinary person (p. 568). This is assessed by considering factors such as the nature, severity and duration of the interference, the character of the neighbourhood, the sensitivity of the plaintiff’s use and the utility of the activity (p. 569). The interference must be substantial, which means that compensation will not be awarded for trivial annoyances (Linden and Feldthusen, at p. 569; Klar, at p. 536).
10. The only basis for an action to recover damages in the circumstances of this case would be the tort of nuisance. Nuisance has been variously described. In this case both parties have suggested definitions and there seems to be little if any dispute between them on the general description of the concept of nuisance. Reference has already been made to the comprehensive definition in Fleming, The Law of Torts. I would add the definition expressed in Street, The Law of Torts (6th ed. 1976), at p. 219:
A person, then, may be said to have committed the tort of private nuisance when he is held to be responsible for an act indirectly causing physical injury to land or substantially interfering with the use or enjoyment of land or of an interest in land, where, in the light of all the surrounding circumstances, this injury or interference is held to be unreasonable.
I am far from suggesting that there are not other definitions, and I do not suggest that the categories of nuisance are or ought to be closed. The above definitions, however, cover the general concept and we must now seek to apply it in the circumstances of this case.
Examples of Nuisance
What Types of Conduct May Become a Nuisance Lawsuit?
As above, whereas nuisance law can be broadly interpreted and applied with great flexibility to a variety of circumstances, the possibilities for cases involving tort of nuisance enables significant creativity. Cases may involve:
Pollutants Including Smoke or Fumes May Be a Tortious Nuisance
- Smith v. Inco Limited, 2011 ONCA 628 (smelting fallout)
- Deumo v. Fitzpatrick, 2008 O.J. No. 3015 (smoke)
- Schenk v. Ontario,  2 S.C.R. 289 (drifting salt from roadway)
- Schuster Real Estate Co. v. Kenny, 1992 CanLII 1941 (restaurant ventilation, smell and noise)
Vibrations Including Noise or Music May Be a Tortious Nuisance
- 340909 Ontario Ltd. v. Huron Steel Products (Windsor) Ltd., 1992 CanLII 7815 (vibrations)
- Gordner v. 2384898 Ontario Limited, 2017 CanLII 9631 (loud music from night club)
- Angerer v. Cuthbert, 2017 YKSC 54 (dogs that bark)
- Milne v. Saltspring Island Rod and Gun Club, 2014 BCSC 1088 (noise from gun club)
- Motherwell v. Motherwell, 1976 ALTASCAD 155 (harassing by telephone)
- Suzuki v. Munroe, 2009 BCSC 1403 (noise from central air-conditioner)
- Banfai et al. v. Formula Fun Centre Inc. et al., 1984 CanLII 2198 (noise from go-kart track)
Bright Lights May Be a Tortious Nuisance
- Cecchin v. Lander, 2019 CanLII 131883 (spotlights)
Trees Including Roots and Branches May Be a Tortious Nuisance
- Mendez et al. v. Palazzi et al., 1976 CanLII 718 (roots)
- Yates v. Fedirchuk, 2011 ONSC 5549 (roots)
- Anderson v. Skender, 1993 CanLII 2772 (branches)
- Freedman v. Cooper, 2015 ONSC 1373 (branches)
- Gallant v. Dugard, 2016 ONSC 7319 (walnuts)
Harassing Neighbour May Be a Tortious Nuisance
- Rathmann v. Rudka, 2001 CarswellOnt 1206 (intentional annoyance)
- Saelman v. Hill, 2004 CanLII 9176 (intentional annoyance)
- Johnson v. Cline, 2017 ONSC 3916 (intentional annoyance)
Other Things May Be a Tortious Nuisance
- Hammer v. Kirkpatrick, 2017 ONSC 7150 (altered water runoff)
- Northern Light Arabians v. Sapergia, 2011 SKPC 151 (grazing horses)
- Desjardin v. Blick, 2009 CanLII 13026 (soil removal with support loss)
Liability Nearly Absolute
Can a Person Be Found Liable In Nuisance Law Even When the Interference Occurs By Something That Is Legal?
It may be surprising to some people to learn that where a nuisance is deemed as a substantial interference in the use or reasonable enjoyment of the property of others, the lawfulness of the conduct or activity involved is almost irrelevant. Accordingly, the tort of nuisance is based more on the harm caused than the wrongfulness. Indeed, in some circumstances, such as occurred in the Schenk case where salting of the Q.E.W. highway was damaging adjacent orchards, conduct may be deemed as a tortious nuisance despite that the conduct is both legal and is legally required. The principle that conduct may be deemed a tortious nuisance despite the conduct being fully legal without conflicting with noise by-laws, without negligence, or without any other wrongfulness, was well stated in the Suzuki case as well as the Gordner case while citing the Supreme Court in the Antrim case and wherein each it was respectively said:
 As can clearly be seen from the authorities, a nuisance may be created even where the activity complained of is otherwise lawful.
 In particular, compliance with local municipal bylaws does not mean that the activity complained of cannot be a nuisance: Kenny v. Schuster Real Estate Co. (1992), 1992 CanLII 1941 (BC CA), 10 B.C.A.C. 126 (C.A.).
 The invasion complained of must be substantial and serious, and it must be clearly unacceptable according to accepted concepts of the day.
 Negligence is not required to make out the tort of nuisance. The converse is also true: the existence of due care will afford no defence if the other ingredients of the tort are present.
 On the question of lawful conduct the Court says:
Para. 29 A finding of reasonable conduct will not, however, necessarily preclude a finding of liability. The editors of Flemings the Law of Torts put this point well at s. 21.120
Unreasonableness in nuisance relates primarily to the character and extent of the harm caused rather than threatened….[T]he “duty” not to expose one’s neighbors to a nuisance is not necessarily discharged by exercising reasonable care or even all possible care. In that sense, therefore, liability is strict…
Furthermore, what is legal conduct that provides comfort and serves a genuine purpose with a benefit for one neighbour may still be a tortious nuisance if such a benefit causes reduced comfort a neighbour. This was also well stated in the Suzuki case involving noise from an air-conditioning unit where it was said:
 One of the factors to be considered in deciding whether a nuisance exists is the social utility of the activity complained of. Here, the air conditioning was installed by the Munroes in order to enhance the comfort of their own home. Their enhanced comfort should not come at the expense of significantly reduced comfort for their neighbours. Nor should the Suzukis be required to close up their windows and acquire an air conditioner in what might be considered self-defence.
Does Nuisance Law Only Apply to Conduct That Interferes With the Use or Enjoyment of Land?
There is also law to indicate that tortious nuisance may occur where conduct interferes with something other than land whereas such was found when the Toronto Harbour Police were found liable in nuisance for interfering with the enjoyment of boating; Poole v. Ragen, 1958 O.W.N. 77.
Does Nuisance Law Only Apply When Interferences Originate From Adjacent Land?
Additionally, there are cases to show that a tortious nuisance can emanate from somewhere other than adjacent land. This was well explained in the case of Bridges Brothers Ltd. v. Forest Protection Ltd., 1976 CanLII 1251 where it was said:
The alleged nuisance falls within the second category of private nuisance defined in Salmond on the Law of Torts, 16th ed. (1973), at p. 51 as
the act of wrongfully causing or allowing the escape of deleterious things into another person's land — for example, water, smoke, smell, fumes, gas, noise, heat, vibrations, electricity, disease-germs, animals, and vegetation.
The author points out at p. 52 that while a nuisance is usually created by acts done on land in occupation of the defendant adjoining or in the neighbourhood of the plaintiff's land, that is not invariably the case. A nuisance may be created elsewhere, "e.g., on a highway adjoining the plaintiff's land, or in a navigable river, or in some place of public resort". It takes little effort or imagination to extend the application of the principle from highways and navigable rivers to the air.
In Gertsen et al. v. Municipality of Metropolitan Toronto et al. (1973), 41 D.L.R. (3d) 646 at pp. 682-3, 2 O.R. (2d) 1, Lerner, J., in the course of a most interesting and helpful judgment, quoted from the judgment of Devlin, J. (as he then was), in Esso Petroleum Co., Ltd. r. Southport Corporation,  A.C. 218 at pp. 224-5:
I think that it is convenient to begin by considering whether there is a cause of action in nuisance. It is clear that to give a cause of action for private nuisance the matter complained of must affect the property of the plaintiffs. But I know of no principle that it must emanate from land belonging to the defendant. Mr. Nelson cited Cunard v. Anti fire Ltd.,  1 Κ.Β. 551; 49 T.L.R. 184, and I think that the statement of the principle is put there as clearly and concisely as it can be. Talbot J. said,  1 Κ.B. 557: `Private nuisances, at least in the vast majority of cases, are interferences for a substantial length of time by owners or occupiers of property with the use or enjoyment of neighbouring property; and it would manifestly be inconvenient and unreasonable if the right to complain of such interference extended beyond the occupier, or (in case of injury to the reversion) the owner, of such neighbouring property.' It is clear from that statement of principle that the nuisance must affect the property of the plaintiff; and it is true that in the vast majority of cases it is likely to emanate from the neighbouring property of the defendant. But no statement of principle has been cited to me to show that the latter is a prerequisite to a cause of action; and I can see no reason why, if land or water belonging to the public, or waste land, is misused by the defendant, or if the defendant as a licensee or trespasser misuses someone else's land, he should not be liable for the creation of a nuisance in the same way as an adjoining occupier would be.
Can a Landlord Be Found Liable In Nuisance Law When the Interference Is Due to Conduct By a Tenant?
In general principle, a landlord will be without liability for nuisances arising from the conduct of a tenant, either residential tenant or commercial tenant; however, where a landlord permits the creation of a nuisance within a tenancy agreement, or where the landlord holds some aspect of control over the conduct that occurs upon the rented premises, and that conduct causes a nuisance upon a neighbour, a landlord may be held liable. Albeit a case from the Small Claims Court and therefore without binding authority, these principles were stated clearly within the case of Fiuza v Creekside Real Estate Group Inc., 2019 CanLII 45625 where it was said:
 Generally, a landlord is not liable in nuisance if his property is in the control of a tenant. A landlord may be liable if he permits the creation of a nuisance in the tenancy agreement, or if the landlord continues to exercise a degree of control over the premises leased, such that a failure to abate the tenants’ nuisance was unreasonable. A landlord may be liable in situations where he leases property and the intended use conflicts with the neighbours, or is likely to cause a disturbance, such as a night club in a residential area or an asphalt plant in a subdivision. This is not the situation here.
As indicated by the notations as well as the cases cited above, nuisance law can contain many surprising twists and turns; and accordingly, obtaining a professional review and opinion regarding nuisance issues is strongly encouraged.
The topic of tortious nuisance is a very deep legal subject with many subtopics that can only be lightly touched upon within a webpage article. Legal practitioners and scholars could spend hours discussing the various twists and turns that apply to the principles and concepts mentioned here.