Newark, N.J. — High school history teacher Yvette Jordan and her husband Frank are among thousands of Newark residents urged to use bottled water until further notice. Recent tests by the Environmental Protection Agency (EPA) showed the 38,000 water filters handed out by the city might not be effective in removing lead from Newark's water supply.

"We had our water tested and it's three times the federal action level," Yvette told CBS News. "So that's upsetting."

Newark is catching up to a problem it's reportedly denied for more than a year. But Mayor Ras Baraka said the water giveaway is out of an abundance of caution.

"The testing was performed in only three homes, which we believe is a small sample size," Baraka said a press conference.

The lead is suspected to be leaching into the water from old pipes in predominantly lower income and minority neighborhoods.

The National Resources Defense Council (NRDC), which is suing Newark for violating federal safe drinking water laws, estimates that 30 million Americans drink community water that contains lead. And 5.5 million get water that exceeds the EPA's maximum levels.

"We need to make some investments in fixing our lead contamination problems," said NRDC's senior director Erik D. Olson. "They have been with us for decades but they continue to haunt us and they are threatening children across the country."

The mayor said the lead service pipes have to be replaced at an estimated cost of $70 million. He has asked President Trump for federal assistance.

"I'm extremely concerned for my students," Yvette said. "Water is a human right. Fix it!"