Officials in Leyden Township near Franklin Park say IDOT crews working on the Fullerton Avenue bridge over Silver Creek damaged the water main running through the creek bed.
Because of the damage, a boil order is in effect for more than 12,000 residents in the township.
The boil order is in effect for the next 72 hours until 10:30 Friday morning.
Residents are urged to boil their water before cooking or drinking.
