"This is a tragedy of staggering proportion and shocking that it's happening in the middle of our country," the Oscar winner said.
The city's 100,000 residents haven't had safe water to drink since 2014, when officials began drawing water from the Flint River as a cost-saving measure. However, the city did not treat corrosive water properly, which led to metal leaching from old pipes.
The crisis prompted President Barack Obama to sign an emergency declaration clearing the way for federal aid.
Cher said she reached out to friend Brad Horwitz, who is an investor in the water company Icelandic Glacial. He contacted company leaders who agreed to double Cher's donation. The 181,440 bottles are expected to reach the Food Bank of Eastern Michigan starting Wednesday.