Generally, municipal smoke-free bylaws are enforced by municipal bylaw enforcement officers, sometimes with the assistance of off-duty police officers (as in the Region of Waterloo).
It is important to note that such bylaws are in the main self-enforcing.
Onus is increasingly being placed on proprietors to ensure compliance with smoke-free bylaws, a requirement which is permitted by the Ontario Municipal Act. While proprietors sometimes complain that this inappropriately makes them "smoking police", there is in fact very little difference between a proprietor's enforcement status with respect to patrons who behave inappropriately after having drunk too much, and actions required toward patrons who smoke illegally. It is important to point out to proprietors who have concerns in this area, that they and their staff simply need to ask those smoking illegally not to do so, refuse to serve anyone who persists in smoking illegally, and eject the very few remaining patrons who may still persist in smoking illegally. As a last resort, bylaw enforcement officers and/or local police can be called. This is exactly the same type of increasing intensity of enforcement that proprietors and their staff routinely use with drunk patrons.
At the municipal council level, however, concern is frequently expressed about a lack of resources, either funds to pay for additional bylaw enforcement officers, or the fact that a municipality may not have any enforcement personnel at all. This is one of the areas where the province's lack of involvement in this issue is most keenly felt: availability of funding to hire contract enforcement personnel - usually only for the first 3-12 months of a bylaw's existence - would encourage many additional municipalities to pass smoke-free bylaws.