All persons subject to the requirements of Illinois State Law should plan and conduct their excavation work consistent with reasonable business practices. 

Conditions may exist making it unreasonable to request that locations be marked within the normal 48 hour (two-working days) notice.  It is unreasonable to request owners and operators of underground utility facilities to locate all of their facilities in an affected area upon short notice in advance of a large or extensive non-emergency project, or to request extensive locates in excess of a reasonable excavation or demolition work schedule, or to request locates under conditions where a repeat request is likely to be made because of the passage of time or adverse job conditions.