(CBS) -- Is Chicago water safe to drink? When it comes to lead levels, that's a dicey question.
A recently completed study by the U.S. Department of Environmental Protection found the testing methods it requires water utilities to use nationwide systematically misses high lead levels.
That can pose health hazards for everyone living in older homes, most of all for children.
When Sara Kopp was told her daughter Isabel had high lead levels that came from the lead-based paint on the windows of their older building, she was shocked.
"I was devastated to find out the apartment we actually moved into was causing my daughter delays in learning speech," Kopp said.
Later, Isabel's doctor told her lead could also be in their drinking water.
"Lead impacts brain development, cognitive development, behavioral development," says Dr. Helen Binns, a doctor at Lurie Children's Hospital. "There is no safe level of lead identified for anyone."
Homes built prior to 1986 likely have lead service lines. Others may have copper pipe connected with lead solder. Some brass faucets may also be a source for lead that can get in your drinking water.
The U.S. EPA requires water utilities to test the drinking water in a small sampling of homes
every three years. But now, EPA scientists have found that the test they have required the city to use for the last 20 years underestimates the amount of lead in drinking water.
Why? Under the current protocol only the first liter of water from the faucet after six hours of no water being used in the house. The EPA's new study took 12 samples and picked up some high lead levels in water further along the service lines, in effect testing all of the water as it flows from the water main.
The findings were not surprising to experts such as Marc Edwards, a professor of engineering at Virginia Tech University.
"We've known this for about 10 years now, that the way in which we're sampling is missing the worst of the problem," he says.
What does surprise Edwards is how long it has taken for the federal government to acknowledge the studies and do something.
"It's shocking it took this long to prove the obvious," he says.
The U.S. EPA study also found street repair work increased lead levels in the drinking water for nearby homes for a lengthy time.
"The group with the highest lead had had some disturbance to the water lines within the past five years. Yikes! Five years and it's still high," Dr. Binns says.
The Chicago Department of Water Management regularly adds orthophosphate to water to reduce lead levels.
"It coats the lead service lines, and it inhibits the degradation of lead into the water," Water Commissioner Thomas Powers says.
Powers says the city cooperated with the EPA study, and despite its results, he believes
Chicago water is safe to drink.
"I drink the water," he says. "My children drink this water."
Susan Hedman, the regional administrator of the U.S. EPA here says the information from the study will be presented to the National Drinking Water Advisory Council, which advises the federal agency on changes to the testing protocol.
"We want to address this as quickly as possible," Hedman says.
She adds: "Everyone, regardless of the age of their home, should always take precautions to reduce the lead in drinking water."
One recommended method to reduce the risk is to flush your water lines after they have not been used for a period of time -- overnight, for example. Taking a shower, running the dishwasher will flush the lines; or, you should run your water for three to five before drinking it.
If you live in an older home with lead service lines and are concerned you can also ask the city to test your water by calling 311 or hire a private laboratory accredited by the Illinois Department of Public Health to test it.
Officials also say homeowners can buy water filters for faucets used to get drinking water. But make sure the one you buy can filter out lead.
Here are some links that can help you find water filters certified to filter out lead, as well as other suggestions from the U.S. EPA to reduce lead levels in your water.
Search for water filters certified to filter out lead:
Search for a testing facility to test your water:
More advice from the EPA to reduce lead levels in your water:
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