If you rent out a property that is designated, advertised, or stated anywhere as a “non-smoking” area, than your tenant should comply with that rule.  However, if you observe your tenant smoking, or have received complaints or suspect that your tenant is violating your non-smoking premises policy, than this letter is a well-worded warning letter which should be given to your tenant. In a dulpex, tri-plex, condo, or multi-unit building, smoking tenants in non-smoking areas must be confronted quickly.  The obvious danger to you as a landlord is the perception that if you let one tenant get away with it, others will use that permissiveness to justify their own rule infractions.  Nipping this in the bud (so to speak) is the proper course of action. Note:  Some jurisdictions protect smoker rights.  While the laws may not allow you to take action against a tenant who smokes per se, a strongly worded letter will indicate to your tenant that you are unhappy with the smoking violation and that the tenant is being observed.  Often, this is all that’s necessary to stem a violation of building policy like this — even if technically you’re not permitted to take further action.