In order to help contractors and private residents avoid existing utility lines (including gas, electrical, and water lines) when digging, the Chicago Department of Transportation maintains 811 Chicago, a free, 24-hour service to private contractors and homeowners in Chicago. Anyone planning to dig within Chicago must obtain a “dig ticket” from 811 Chicago. 811 Chicago notifies all utilities of the impending excavations. The utility owners then send out staff to mark the location of the underground facilities within 48 hours (excluding emergencies), not counting Saturdays, Sundays, and holidays. This dataset shows these utility notifications. Since it is common for the same dig ticket to produce multiple notifications, the same dig ticket will appear multiple times and this dataset cannot be used without further refinement to count, map, or analyze unique excavations in Chicago. See https://ipi.cityofchicago.org/Digger for more information on the dig ticket system.