A Kankakee River levee near Hebron, Ind., breached Friday afternoon, officials said.
The break occurred at roughly N 700 W and the Kankakee River.
There is widespread flooding in the area and emergency evacuation services are on scene to assist residents, officials said.
First responders prepared for boat rescues in the Ramsey's Road subdivision near DeMotte, where about 30 to 40 homes are in the path of the rising waters.
Residents are being told to evacuate immediately. No injuries have been reported.
The problems began mid-afternoon Friday with a relatively small breach of the riverbank. The barrier to the Kankakee River is natural, not manmade.
Sandbags and heavy equipment were brought in, but the breach only got bigger and grew to at least 30 feet wide.
By nightfall rising waters had started to surround some homes.
Most of the residents have chosen to stay despite the request to evacuate, so boats are being kept at the ready in case rescues are necessary.
"Get out. That's my message. Get out. You're in there. You're not going to save your home at this point. And all you're doing is endangering the lives of the first responders," said Chief Randy Woods, Keener Township Fire Department.
It's been touch-and-go the last couple days for people who live along the Kankakee River in northwest Indiana, after the river crested at record levels at various points. The levels have not really receded and it's been a bit of a waiting game with more rain in the forecast this weekend.
First responders are planning to stay in the subdivision at least through Saturday morning. Officials said it's hard to know how much higher the water is going to rise.