Belmont Area police say suspects are targeting the elderly.
The con men pose as city workers to enter a home, then rob the victims. They often say they work for the water department and need to check the water inside the home.
Most of the robberies have been between noon and 6 p.m.
The descriptions of the con men vary, but there are two to three white or Hispanic men between 30 and 45 years old, police said. The heights and weights vary from 5-feet-7 to 6-feet with a medium to heavy build.
Police say residents should secure windows and doors, pay special attention to people loitering in the area and report suspicious people or activity to police.
The Sun-Times Media Wire contributed to this report.