West Yorkshire Police were called to Newlands Crescent in Morley at 6.14pm on Thursday to reports of a domestic-related incident.
A 37-year-old man had been assaulted and received burn injuries from boiling water.
He is continuing to receive treatment in hospital.
His injuries are not considered life threatening.
An 18-year-old man has been arrested on suspicion of wounding with intent and is currently in custody.
Officers from Leeds District Safeguarding Unit are continuing to carry out enquiries into the incident.