On June 10, Hunter was in his room at a Dunedin boarding house when an argument erupted over his benefit.
He hit his girlfriend in the face.
Hunter then began overturning furniture in his room, which led to him knocking over the jug of scalding water that had been resting on a chest of drawers.
"The victim started screaming with intense pain, the defendant continued to yell at the victim for another 15 minutes," a police summary said.
After Hunter left the scene officers arrived to find the woman "extremely upset".
She stood under cold water in the shower in a bid to ease the pain in her legs before seeking medical attention.
The court heard she remained supportive of her partner.
When Hunter — a patched gang member — was interviewed by police, he admitted what had happened.
While the defendant had spent the last six weeks in prison, Judge Robinson noted he had been on electronically monitored bail for seven months with his parents on the West Coast.
Though Hunter was assessed as high risk of causing harm to others, the judge said he had done well on bail.
He was keen to find work but that would be unlikely should he be sentenced to home detention, counsel Cate Andersen said.
Judge Robinson imposed five months' community detention (to be served on the West Coast), 200 hours' community work and nine months' supervision.