The plumbers, representing the United Association of Journeymen and Apprentices of the Plumbing and Pipe Fitting Industry, visited over 1,100 Flint homes to help install new faucets and water filters free of charge.
Local United Association member Harold Harrington welcomed the volunteer workers with a rousing speech.
"We did not cause this American tragedy in Flint, but we certainly can help correct the damage that has been done!" he said to the group, according to Michigan Radio.
The workers were paired up, given a list of addresses and handed filters and faucets donated by Plumbing Manufacturers, International.
Two plumber volunteers from Local 333 await a homeowner in Flint as they distribute water and install filters.Posted by The Michigan Building and Construction Trades Council on Saturday, January 30, 2016
Many Flint residents were in desperate need of installation help because their existing faucets were too old to accommodate new filters intended to remove the excess of lead found in the town's water.
"We know when we've been going door to door servicing inbound people that many fixtures are old, the faucets, and they don’t adjust to the filters," Genesee County sheriff Robert Pickell told ABC12 on Saturday.
The sheriff added that Flint residents were grateful for the kindness of the volunteer plumbers.
"They're here to donate their time and skill over the years that they've learned this trade and put it to good use today for people that are vulnerable," he told the station.
Cases of water are distributed at Flint Local 370.Posted by The Michigan Building and Construction Trades Council on Saturday, January 30, 2016
Although the new faucets are a comfort to Flint residents, they only filter out 150 parts per billion (of lead) – and some residents have up to 4,000 ppb.
On Tuesday, a spokeswoman for the U.S. Attorney's Office in Detroit announced that the FBI has joined a U.S. criminal investigation into the water contamination crisis occurring in Flint, reports Reuters.