Police said Jorden R. Lester, 22 and his 28-year-old girlfriend were there when employees noticed the woman had bruises, cuts on her face, and had difficulty walking.
They pulled her aside and got the attention of off-duty Trenton Police Officers who were working at the welfare office.
The officers questioned the woman, and said she told them she jumped, but after more questioning she said her boyfriend had been assaulting her with a plunger and a wrench for the past week.
Lester was arrested and charged with aggravated assault, unlawful possession of a weapon and terroristic threats.
Bail was set at $75,000.
The victim was treated for fractures to both legs and her nose then given shelter.