Some 180,000 residents in Jackson, Mississippi have “indefinitely” lost access to reliable running water after excessive rainfall and flooding.
Rising floodwaters over the weekend breached the city’s main water treatment facility, bringing it to the brink of collapse.
A state of emergency has been declared, and schools, restaurants and businesses have temporarily closed.
The city had already been under a boil-water notice for a month.
Problems at the OB Curtis Water Plant began after heavy rains caused the Pearl River to crest and spill over onto city streets over the weekend.
City hall confirmed on Monday that river water had entered the facility, which treats more than 50 million US gallons (190 million litres) per day.