The notice referred to in Sections 1480.5 and 1481 shall be served upon the occupant or owner of the land, or the person causing, controlling or owning the encroachment, or shall be left at the place of residence of such occupant, owner or person if he resides in the county and is known to the person giving such notice. If the person upon whom notice is to be served does not reside in the county, the notice shall be posted on the encroachment. The notice shall specify the breadth of the highway, the place and extent of the encroachment, and shall require the removal of such encroachment within 10 days.