Water department workers first noticed water bubbling up near highway support pillars north of Biddle Street beneath Interstate 70 on Friday. By Saturday morning, the problem had grown into a sinkhole roughly 30 feet long, 20 feet wide and 10 feet deep, shutting down a major downtown traffic corridor and exposing the challenges posed by St. Louis’ aging infrastructure.
The collapse forced the closure of westbound Interstate 44 between Interstate 64 and Interstate 70, along with several connecting ramps near downtown. Days later, the hole remained a major disruption for motorists and a stark reminder of the aging network of pipes beneath the city.
The collapse was not caused by a single broken pipe.
Robert Atchisson, a spokesman for the St. Louis Water Division, told the St. Louis Post-Dispatch that an initial failure in a 20-inch water main triggered a sewer washout beneath the roadway. The washout then led to the collapse of a 12-inch main and a 10-inch main into the excavation site.
Water from the three failed mains that gushed into a sewer line beneath the sinkhole has been shut off, Dennis Tullock, the city’s distribution superintendent, told the Post-Dispatch.
The chain reaction created a sinkhole large enough to close one of downtown’s busiest highway connections and launch a multiagency response involving city departments, state transportation officials and utility crews.
Mayor Cara Spencer said the city activated multiple municipal departments, along with the Missouri Department of Transportation and utility companies, to assess conditions, secure the site and coordinate repairs.
The incident has also renewed attention on the condition of St. Louis’ water infrastructure.
Spencer said isome of the failed water lines were more than 100 years old.
“Situations like this, of course, remind us that our city’s great history comes with aging infrastructure,” Spencer said.
The mayor cited the collapse as another example of the need for additional investment in the city’s water system. A proposal before the Board of Aldermen would increase water rates about 90% over six years, beginning with an 18% increase July 1 if approved.
“With the rates that we’ve had, we have not had the income necessary to do regular replacement of the lines,” Spencer said. “These lines were over 100 years old, and so you’re seeing decades of deferred maintenance.”
The city also has redirected millions of dollars in unspent federal COVID-19 relief funds and Rams settlement dollars toward water-system improvements.
The collapse raised concerns about whether unstable ground conditions beneath the interstate structure may have contributed to the sinkhole.
According to Spencer and city officials, scientists with the Missouri Geological Survey inspected the area and found no indication that geological conditions caused the collapse. Preliminary findings indicate the sinkhole was caused by the failed utility lines rather than broader geological issues beneath the bridge.
State and city agencies continue to assess the damage and coordinate repairs.
Officials have not announced a firm reopening date, though KSDK reported that repairs are expected to take at least a week.
While crews continue working to stabilize the area and replace damaged infrastructure, the sinkhole has become a visible reminder of the challenges facing older cities whose underground systems were built generations ago.
For drivers, the disruption is measured in detours and delays. For city leaders, it has become another warning about the cost of maintaining infrastructure that, in some cases, has been in service for more than a century.
Sylvester Brown Jr. is the Deaconess Foundation Community Advocacy Fellow.