Joliet police said Jose Valezquez-Flores was hired to make repairs on April 25 at a home on Silver Ridge Drive. Police were notified of the incident on May 7.
While at the home, Valezquez-Flores allegedly had inappropriate sexual contact with a 16-year-old girl.
Investigators said Velazquez-Flores admitted to the crime during questioning on Tuesday, and he is now in custody.
No further information was immediately available.