In the pre-dawn hours of April 13, early-morning flooding affected a number of basements, lower-level businesses and building mechanical rooms in Chicago’s Loop, the city’s central business district. The flooding was concentrated in low-lying subterranean spaces and led to property damage, temporary disruptions to some building operations and emergency responses by city crews and private contractors. Reports from building managers and local officials indicated that intense localized runoff and possible drainage system overloads contributed to the inundation. In downtown areas with older infrastructure and combined sewer systems, heavy surface runoff can enter basements through window wells, stairwells and failing drains. Though exact rainfall totals and causes for this specific April 13 event varied by location, the pattern—rapid accumulation of water in subterranean spaces during a brief heavy downpour or drainage failure—is consistent with prior urban flash-flood incidents in Chicago. The affected buildings included commercial office properties, retail storefronts with lower-level storage and several food-service establishments that operate partially below street level. Building staff reported water levels reaching inches to more than a foot in some basements, damaging inventory, electrical equipment and HVAC components. In some cases, water entered mechanical rooms, prompting concerns about electrical hazards and equipment damage. Property managers closed impacted areas to employees and customers while coordinating with restoration firms. Chicago Fire Department personnel and Department of Water Management crews responded to calls for assistance. Emergency responders focused on ensuring occupant safety, isolating electrical systems when necessary and supporting evacuations from basement spaces. City crews and contractors deployed pumps and began water removal and drying operations later in the morning. Where water levels receded, building owners arranged for inspections of mechanical and electrical systems before restoring normal operations. Public transit impacts were localized but noteworthy. Lower-level retail corridors connected to some commuter rail and pedestrian tunnel systems experienced temporary closures as water was cleared and surfaces made safe. CTA subway operations were not broadly suspended citywide, though riders were advised to expect delays on affected routes and to follow official transit alerts for the latest status. Infrastructure experts and city officials noted that basement flooding in the Loop often reflects a combination of intense precipitation, aging stormwater infrastructure and the area’s high proportion of below-grade spaces. Chicago’s downtown contains numerous buildings constructed before modern waterproofing and drainage standards; when storm drains surcharge or downspouts and nearby street inlets become overwhelmed, water can find paths into subterranean rooms. Property owners are frequently advised to maintain sump pumps, backflow preventers and to coordinate with city drainage services before and after major storms. No confirmed fatalities were reported in connection with the April 13 flooding. Injuries, when reported, were generally minor and related to slips or brief medical issues during evacuations; detailed injury and damage assessments were being compiled by building owners and insurers in the days following the event. Financial impacts, including business interruption and repair costs, were expected to vary widely by property and the extent of mechanical or inventory damage. City officials urged building managers and residents in basement-prone areas to report flooding and to check for hazards such as damaged electrical panels, contaminated water, mold risk and compromised mechanical equipment. They also reiterated guidance on safe restoration practices: turn off electricity to flooded areas if it can be done safely, avoid entering standing water that may be contaminated, document losses for insurance claims and employ qualified contractors for cleanup and repairs. As officials and property owners continued assessments, the event underscored long-standing resilience questions for Chicago’s downtown: how to adapt infrastructure and building practices to reduce basement flooding risk in the face of episodic heavy rainfall. Efforts to mitigate such risks involve a mix of property-level measures (sump pumps, backflow valves, improved waterproofing) and public investments in stormwater infrastructure, priorities that city planners and stakeholders revisit after each notable flooding episode.