The Flint water crisis begins when officials at Flint, Michigan switch the city's water supply to the Flint River, leading to lead and bacteria contamination.

The Flint water crisis was a public health crisis from 2014 to 2019 which involved the drinking water for the city of Flint, Michigan, being contaminated with lead and possibly Legionella bacteria.

Flint is a city in and the county seat of Genesee County, Michigan, United States. The population was 81,252 at the 2020 census, and was estimated to be 79,735 in 2024. making it the largest city in Genesee County and the 12th-most populous city in Michigan.

The Flint River is a 78.3-mile-long (126.0 km) river in the Flint/Tri-Cities region of Michigan in the United States. The river's headwaters are in Columbiaville in Lapeer County and flows through the counties of Lapeer, Genesee, and Saginaw. The cities of Lapeer, Flint, Flushing, and Montrose are along its course.

Lead poisoning, also known as plumbism and saturnism, is a type of metal poisoning caused by the presence of lead in the human body. Symptoms of lead poisoning may include abdominal pain, constipation, headaches, irritability, memory problems, infertility, numbness and tingling in the hands and feet. Lead poisoning causes almost 10% of intellectual disability of otherwise unknown cause and can result in behavioral problems. Some of the effects are permanent. In severe cases, anemia, seizures, coma, or death may occur.

Legionnaires' disease is a form of atypical pneumonia caused by any species of Legionella bacteria, quite often Legionella pneumophila. Signs and symptoms include cough, shortness of breath, high fever, muscle pains, and headaches. Nausea, vomiting, and diarrhea may also occur. This often begins 2–10 days after exposure.