Marlo Ann Shamblin pleaded guilty last week to aggravated battery.
Nampa police responded to a shelter on April 17, where they found a 30-year-old Meridian man with serious burns to his stomach, back and arm. The victim was later taken for treatment at the burn unit at the University of Utah Medical Center in Salt Lake City.
Shamblin poured boiling water on the man after asking him to leave the residence.
She faces up to 15 years in prison. Sentencing is scheduled for Dec. 11 before Canyon County District Judge George Southworth.
Shamblin had a previous battery conviction in Gem Country from 2007. She was convicted in Ada County of disturbing the peace in cases from November 2010 and January 2011. She was originally charged with battery in both of those cases, with the charges reduced in exchange for her guilty pleas.