In the spirit of getting on the cannabis bandwagon and joining in with comments about how legalization is going to change the landlord and tenant law landscape I want to make the comment: "relax, the sky is not falling, and it will be fine". Landlords and tenants can take comfort in knowing that their homes and buildings will not soon be engulfed in the haze of marijuana against which they have no recourse "because it's legal". Cannabis legalization does not allow others to impose their second hand cannabis smoke on unwilling neighbours and guests. Legalization does not override properly crafted no-smoking rules and contractual clauses (in leases) that prohibit smoking in residential units and the common areas of a building. Legalization is not expected to rob the users of cannabis of decency and respect for neighbours and non-users. For the most part, a polite conversation with smokers advising what the problem is will likely solve it. I don't imagine that users will intentionally continue to bother their asthmatic neighbour, allergic superintendent, or other uncomfortable resident with their "dope smoke" because it's legal. Most people are decent and I think it is reasonable to expect responsible and respectful behaviour from smokers---starting day 1. Most of these users, I'd suspect, are already smoking and consuming in a way that doesn't bother neighbours, landlords, and others, even though it isn't just legal "yet".
In the event of those few people who feel emboldened by "legalization" and who plan to smoke their dope wherever they please---well, those people will discover that the law has some teeth to prevent the interference with reasonable enjoyment of a rental property by smoking "legal" cannabis. Tenants should know that the law does not put the burden on them to deal with nuisance "dope smoke" and the law does not require them to take on the legal challenge of evicting the cannabis user. Tenants who are bothered by marijuana smoke-even though the marijuana is legal---may legitimately complain to their landlord and the landlord has a duty to take action to stop the problem. Stopping the problem may include eviction, it may include just a conversation and education, it may mean providing a suitable smoking area, it may mean co-operation to ensure that the smoker can smoke and those who don't like the smoke don't need to inhale or be exposed. In the event that a solution cannot be found the ultimate answer is that the cannabis smoker will be evicted if their behaviour continues to be disruptive.
Aside from "substantial interference with reasonable enjoyment", there are other bases to challenge the cannabis smokers in a building. Non-smoking clauses are enforceable, even against a legal product like cannabis and tobacco, if the tenants are contractually prevented from "smoking" in the residential complex. There is no "right to smoke" over-ride in the legalization that voids non-smoking clauses. Hence, landlords, take comfort that this will not be a free for all.
The legalization of cannabis does now invite a conversation at the time of renting and amongst tenants in tenant associations. The conversation about tobacco smoking has been happening for years (i.e. non-smoking building), and people have made choices based on the landlord's policy on smoking in the building. These conversations now should happen, openly, between prospective tenants and landlords in relation to cannabis as well. In fact, the cannabis conversation is likely more important than the tobacco conversation as cannabis use and the reason for use is not entirely recreational.
Of course we will see what un-anticipated problems arise with legalization. While it may be worrisome, the Residential Tenancies Act is fairly robust and solutions to most problems can be found within it.