FLINT, Mich. -- Residents in Flint may still be a few years away from drinking unfiltered tap water as the city makes incremental progress on an ambitious -- if not overly optimistic -- timeframe to replace old water service lines that leached lead into homes and businesses.

Retired National Guard Brig. Gen. Michael McDaniel, who coordinates the FAST Start initiative, said he has a goal of finishing the pipe replacements for residents in 2019 by fixing service lines to 6,000 homes a year. The city has estimated that lines to 20,000 homes need to be replaced.

“So far, I’d say it’s been going slow,” McDaniel said. “We wanted to replace 1,000 service lines in the city of Flint in 2016 and we are still working on that contract even today because we’ve had a fairly warm winter.”

As of last week, lines to fewer than 800 homes had been replaced with new copper pipe. The effort has been plagued by problems that include inaccurate records on the location of pipes and the type of material used in them. Funding for the project beyond this year is also uncertain.

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The effort comes as some residents in the impoverished city where 57 percent of the roughly 100,000 residents are black still do not trust the government because of failures that led to the lead-tainted water crisis. To save money while under state control, the city began using water from the Flint River for in April 2014 without treating it to prevent corrosion in steel pipes. Residents’ complaints about color, odor and taste were downplayed by the government until elevated levels of lead, a neurotoxin, were detected in children. Twelve people died in a Legionnaires’ outbreak that has been linked to the improperly treated water.

The state finally acknowledged the lead problem in October 2015, but pipes were already so corroded that simply switching the water supply to a new source didn’t clear up the problem. The overall lead level in Flint’s water still exceeds the federal limit, and authorities require residents to use state-provided faucet filters.

Researchers testing the water in Flint, Michigan. CBS News

McDaniel said the next phase of the project, expected to start in late April, will replace lines to 4½ homes a day in 10 different zones, which is 225 a week and 900 homes a month.

“That’s a tough goal,” McDaniel said. “That means we’ve got to have people out there and we don’t have those people on staff for the city yet.”

Because of inaccurate records, a number of homes that have been targeted turned out to have copper pipes that didn’t need to be replaced.

Then there’s the issue of money.

“We have enough money to do 2017, we’ve got about half the money we need for 2018, we don’t have money for 2019,” McDaniel said. “The plan that we have, we will be able to replace all the lead or galvanized service lines in occupied residences in the city of Flint in the next three years. But we don’t have enough money to do it all, so yes that’s absolutely a concern.”

An estimated $106 million to $108 million is needed to finish replacing the 18,000 to 20,000 service lines. The state gave $27 million toward the effort and the U.S. government on Friday came through with a previously promised $100 million to Flint for water infrastructure needs - $40 million of it specifically for pipe replacements.

Residents have mixed opinions on the speed of the project.

“It’s been slow real slow,” said Jeffrey Jones, who has not had his pipes replaced. “They did these (pipes) a couple of weeks ago and then they just stopped. I don’t know. Nobody has come around and said, ‘Hey, this is what were gonna do.’”

Others in Jones’ neighborhood have had their pipes replaced and said it seems to be moving just fine.

“I guess it’s been all right, I’ve got nothing to compare it to,” said Dave Pillen. “It’s been pretty fast here, but what about other places?”

Even after the pipes are replaced and officials give the all-clear to drink unfiltered tap water, some residents say they still won’t trust that the water is safe.

“I don’t think I’ll ever trust them again, been lied to so many times,” said Gary Boedecker, a lifelong Flint resident.