Setback lines – something every homeowner should be aware of when they purchase their house. In the city of Seattle, the DPD lays it out really clearly for you with this diagram:
No portion of your house may encroach on these setback lines. The dimensions are taken from your property line, not necessarily a fence or sidewalk where it may look like your property ends or begins. There are some exceptions if your house already encroaches, then it is most likely grandfathered in and can remain within the setback zone.