CHICAGO (CBS) -- You see them all the time when you're driving: holes in the street that look pretty harmless.
But it turns out, hundreds of holes in Chicago are hiding a dangerous secret.
They could easily become sinkholes and cause a lot of damage.
CBS 2's Pamela Jones talks with some residents who want the problem fixed.
A couple of spots near 73rd and Loomis were on the edge of becoming giant sinkholes, neighbors say.
"Anybody can walk out there. A car can roll by, a truck, and boom -- everything's in the hole," Romona Burwell says.
Residents have been complaining just a thin layer of asphalt has been keeping cars from sinking. But CBS 2 measured one hole, and it was more than 3 feet deep.
Burwell says she's been complaining about the holes for months.
The city's Water Department commissioner says the bigger the hole, the longer it takes to fix.
"It could take a couple of weeks to make a repair like this," Commissioner Thomas Powers says.
He says the city is actually working on 200 areas where old sewer lines laid in sand leak and wash the street away from underneath.
"As the material flows through the sewer, it tends to leach out around through these leaks," he says.
There is still some 1,500 miles of sewer in Chicago that's more than 100 years old. The city says a more permanent fix means replacing that old line.
The commissioner says if you see a hole in the street, call 3-1-1 and report it as a sinkhole or cave-in.
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