Illinois Attorney General Lisa Madigan is suing the operators of Trump International Hotel and Tower for releasing water into the Chicago River in violation of federal environmental laws.
The lawsuit claims the building sucks about 20 million gallons of water out of the Chicago River and returns the same amount 35 degrees hotter. The water is used to cool heating, ventilation and air conditioning systems in the building.
In a statement Madigan said the water is taken without a permit and without any regard to how its return may impact the river's ecosystem.
The lawsuit filed in Cook County Circuit Court says building managers failed to properly renew a permit and have been using river water unlawfully for nearly a year.
Trump Tower officials on Tuesday said the lawsuit "was motivated by politics."