Mr. Baraka has defended the city’s response and rejected comparisons to the situation in Flint. On Saturday, Mr. Baraka urged pregnant women and young children to use bottled water until additional testing was done, but he did not mention the recommendation from the E.P.A. for all residents with lead pipes to use bottled water.

Critics like the Natural Resources Defense Council have called for the city to offer bottled water.

Erik Olson, the defense council’s senior director for health programs, said Mr. Baraka’s announcement was a good first step, but said the city should offer bottled water to even more residents.

“We’re concerned it might be a temporary thing and we’ll be back to where we started with thousands of citizens in Newark continuing to get water that is contaminated,” Mr. Olson said.

On Saturday, Mr. Baraka acknowledged that the city did not know if there was something wrong with its water filters. He urged residents to run their water for five minutes to clear the system of stagnant water before using a filter.

“We don’t know either way,” Mr. Baraka said. “We don’t have enough information to make that determination.”

A spokesman for the E.P.A. said on Sunday that the city “has not yet formally replied to our letter.” The website NJ.com was the first to report on the letter on Sunday.

Mr. Baraka ran for mayor in 2014 as a populist firebrand to succeed Cory Booker, the United States senator who is running for president. When Mr. Baraka was elected to a second term last year, he won praise for balancing new development with fears about gentrification . But he has also received criticism over the water crisis.