The City of La Cañada has instituted some rather strict requirements on home remodeling. Any construction plans that effect the building setback require a survey. This would include the construction of walls and fences on or near property lines. The survey needs to be performed by a licensed Surveyor.
I have recently come across some bizarre requirements coming from the City o f La Canada Flintridge. They have interpreted their new Municipal Code 11.11.050 Residential development standards Section E.1 as to require surveys any time a neighbor complains about new construction within 10′ of the property line. Please post a comment if you have any experience with this kind of issue.
You may want to refer to the La Cañada Flintridge Municipal Code link.