這個律師網站這麽說

http://www.cbabc.org/For-the-Public/Dial-A-Law/Scripts/Housing/400

Fences
Local bylaws often control how high a fence can be, both natural fences, including hedges, and those that are constructed of wood, stone, or other materials. If your neighbour builds a fence higher than the bylaw allows, you can talk to them about it. You can also call the city, which can order the person to obey the law. Absent a complaint, your municipality is unlikely to inspect neighbourhood fences to determine whether they conform with height bylaws.

但不知道這種說法的出處。