Lightfoot announced Tuesday that city officials will halt the installation of water meters in homes with lead service lines after new data from an ongoing study found an increase in lead levels in dozens of homes.
The mayor reassured residents that Chicago's drinking water is safe, and ordered more testing to determine the cause.
"We don't know specifically what the issue is with the meter, we just know that in a certain number of meters we saw an increase in lead levels, therefore we're taking the precaution to make sure that we stop the installation," Lightfoot said.
She also said that no one who has those unsafe levels of lead in their water has been found to have high levels of lead in their blood.
Now some are questioning whether the city is doing enough.
WATCH: Hyde Park homeowner frightened by contaminated water
Hyde Park resident Alysia Tate is dealing with contaminated water at her townhome after city officials installed a water meter several years ago. Tate said she has to run her water through a filtration system to remove lead that's well above the Environmental Protection Agency's safe water guidelines.
"I think they are saying the EPA action level for lead is 15 micrograms per liter," Tate said. "I have readings at 54, 46, 36, and most of the readings are in the 20s."
Tate said she felt scared and disappointed after finding out about the high lead levels at her home.
"It's frightening to think that something you rely on every day to live, water, could be poisoning you," Tate said.
Since the program began in 2009, city officials said water meters have been installed in 179,000 residences. More than 500 of them have been tested and 36 of those homes have lead levels deemed unsafe.
Lightfoot urged concerned homeowners to call the city's 311 number to get their water tested and request a free pitcher.
Alysia Tate has one, but she said that's not enough.
"I'm just one person who happened to agree to have my water tested, the vast majority of Chicagoans have not had their water even tested so they have no idea what they're drinking," Tate said.