By Pam Zekman

(CBS) — The city’s water supply is under attack by a class-action lawsuit claiming construction work to replace old water mains actually causes lead to seep into the water supply.

On top of that, 2 Investigator Pam Zekman has learned the U.S. Environmental Protection Agency will soon be changing the testing standards for lead in your drinking water.

The class-action lawsuit charges the city knew street construction projects disturb lead water pipes, and can stir up lead sediments in the pipe that then leech into the water.

The lawsuit further claims the city “failed to warn” homeowners about the potential danger or to provide “accurate directions” on what they can do protectively.

Thomas Powers, Chicago Water Management commissioner, denies homeowners are not adequately warned before construction projects begin. He says the city delivers a document to each home that tells homeowners how to flush their water lines. A chemical already in the water provides additional protection, Powers says.

“We are continually adding phosphate to the water to ensure that if there are any disturbances to the coating that it immediately begins to re-coat it,” he says.

Critics like Virginia Tech civil engineering professor Marc Edwards say the real problem is inadequate testing procedures documented in a study done by the U.S EPA, in partnership with the Chicago Department of Water Management, several years ago.

“We have to close these loopholes,” Edwards says. “We have to better protect our children.”

Officials tell CBS 2 more than two years ago they were going to change the testing procedures in order to get a more accurate assessment of the amount of lead in drinking water.

Robert Kaplan, the acting Midwest administrator for the Environmental Protection Agency, says there is finally good news on that front. The EPA will begin rolling out better testing procedures in about a month.

“We want to make sure we capture the peak of the lead, the worst case,” Kaplan says.

Using the current testing procedures, a city spokesman says, “Chicago’s water is safe and exceeds federal, state and industry standards.”

The potential problems exist in homes built before 1986, when lead pipes were used in construction.

Sarah Kopp lives in one of those apartment buildings. She turns on her tap for five minutes and then filters the water before giving it to her daughter, Anya.

Anya’s doctor suggested that two years ago, when high levels of lead were discovered in Anya’s blood stream.

“She was actually developmentally delayed a little bit,” Kopp says. “Luckily, they caught it early enough.”

But for now, Kopp will continue with her precautions.

“I do not feel safe drinking this water, without the proper testing being done,” Kopp adds.

Both the EPA and the Chicago Department of Water Management stress that Chicago’s water is safe to drink.

If you are concerned about lead in your water, there are some things you can do:

— Use a water filter that removes lead. But be sure to clean the filter as often as instructed or that could create more problems.

— Run the water for 3 to 5 minutes before first using it each day. You can also simply take a shower or wash the dishes to flush the system.

— Drink only cold tap water.

— Test your water. The city does it for free; just call 3-1-1.

— EPA approved labs charge $25 to $50.