What penalties can a municipality impose if I alter a heritage-designated property without a permit?

A municipality can take enforcement action against an owner who alters a designated heritage attribute without the required approval, which can include seeking a court order requiring the owner to restore the property to its prior condition, in addition to prosecution for the offence itself, which can carry meaningful fines under the Ontario Heritage Act. The Act treats unauthorized alteration and unauthorized demolition of protected heritage attributes seriously, reflecting that the loss or alteration of a genuinely irreplaceable heritage feature can't necessarily be undone simply by paying a penalty afterward.

Because a restoration order can require reversing work that's already been completed, potentially at significant cost well beyond what proper approval would have required, owners should never treat unauthorized work as a faster or cheaper alternative to getting approval first, even where the requested change seems minor or reasonable. If you've already made an unauthorized alteration, whether knowingly or by mistake, getting legal advice promptly and approaching the municipality proactively is generally a better path than waiting for enforcement action to begin, since demonstrating good faith and a willingness to remedy the situation can affect how the municipality responds.