Replacing 15,000 lead pipes is the only way that residents of Flint, Michigan can feel safe again in the wake of a tainted water scandal, the US city's mayor said Tuesday.

"We have been emotionally traumatized and we need new pipes," Mayor Karen Weaver told reporters. "That's the only way the community is going to have confidence in what's going on."

Officials are accused of ignoring months of foul-smelling and discolored water, even as residents complained it was making them sick and tests showed elevated lead levels.

It wasn't until a local pediatrician published evidence of a huge spike in lead poisoning among Flint children in October that state officials admitted the water was unsafe to drink. Residents of the predominantly poor and black city of 100,000 have been using bottled water ever since.

Weaver said crews could begin pulling out pipes within a month if she is able to secure the $55 million needed to replace 550 miles (885 kilometers) of aging, corroded lead pipes with new copper pipes.

The work could be completed in about a year.

Lead exposure can have devastating impacts on young children by irreversibly harming brain development. It has been shown to lower intelligence, stunt growth and lead to aggressive and anti-social behavior.

Governor Rick Snyder -- who is facing calls to resign over his handling of the crisis and has declined requests to testify before a congressional panel investigating the scandal -- has pledged to address the damage done in Flint.

But he has not yet supported calls to immediately begin replacing the pipes, saying that the short-term solution is to restore a protective coating that stops the corrosion.

That simply won't work for Flint, Weaver said.

"We will never be confident that the biofilm has built back on. That's a tough one for us," she told reporters.

The cash-strapped city was reportedly hoping to save $5 million over two years by drawing water from the Flint River beginning in April 2014 rather than continuing to buy it from nearby Detroit.

The US Justice Department launched an investigation into the crisis last month and Michigan's Attorney General Bill Schuette has also launched an independent investigation.

He told reporters Tuesday that the former prosecutors and FBI agents leading the investigation will determine if any laws were broken.

They will also be investigating whether the poisoned water could be blamed for any deaths, which could lead to involuntary homicide charges, special prosecutor Todd Flood said.

When asked if Snyder could be exempt from the investigation due to executive privilege, Todd said: "No one can get away from a crime."