A series of flags or paint lines may appear in front of your property at any time. In Wisconsin, it is a state law that Diggers Hotline must be called before any digging occurs. By calling Diggers Hotline, utilities are notified to mark the locations of their facilities, before any digging can occur. This provides safety for anyone doing any excavation to know they are not near any live utilities like an electrical, gas or telephone/fiber line.
Flags or paint lines do not always mean digging is happening soon. Someone may call Diggers Hotline just for surveying purposes. The City will perform a digital survey before almost all projects. When Diggers Hotline is called, utilities will mark their facilities and the surveyor will shoot the exact location of the utilities for use in a future design.
One way to find out if a City project is planned in your area is by checking the City's project page.