A devastated mother found her teenage daughter collapsed in the bath after her heart suddenly stopped, an inquest has heard.
Fit and healthy Amber Rummels, 18, was found under the water with the taps still running at her family home.
An inquest heard her mum Anita Lewis, 44, pulled Amber out of the bath and carried out CPR (cardiopulmonary resuscitation).
Paramedics managed to get Amber's heart started but she died four days later in hospital.
Medics believe waitress Amber died of sudden arrhythmic death syndrome - a cause of unexpected deaths in young people.
In a statement to the inquest, Anita said she woke in the night to find the house with no electricity.
Anita said: "Water was coming through the light fitting in the hallway. I could then hear a dripping sound of water coming from the bathroom."
The inquest heard she grabbed a pen and managed to unlock the bathroom door.
She said: "I looked into the bath and I saw the water was running from both taps. Amber was lying in the foetal position.
"I grabbed Amber out of the bath under her arms and I put her on the floor."
The inquest heard Anita performed CPR on her daughter until paramedics arrived.
An electric facial exfoliator was in the bath with Amber but the inquest heard it was unlikely it could have caused an electric shock.
John Biggs, who works for Western Power, visited the family home in Llandaff, Cardiff and found no faults with the electrics.
The inquest heard Amber was studying a hospitality course at Cardiff and Vale College. She had been working at the college's restaurant, called The Classroom, on the day of the incident in December last year.
Her boss said Amber did not complain about being ill and appeared her "happy normal self."
A post mortem examination found Amber died from hypoxic brain injury and necrotising bronchopneumonia due to near drowning due to sudden arrhythmic death syndrome.
Consultant pathologist Dr Meleri Morgan said Amber also suffered burns to her face likely to be from the hot water tap.
Dad Steven Rummels, 47, said: "Amber was a strong character. She was fun and caring and we will all miss her dearly."
The inquest heard younger sister India and brother Drake are to undergo medical screening of their hearts.
Coroner Graeme Hughes recorded a narrative conclusion.
He said: "Amber Rummels ultimately died from a combination of hypoxic brain injury and pneumonia.
"She is likely to have experienced an arrhythmia while in the bath leading to a lack of consciousness and near drowning."
He added it is "possible but unlikely" that the exfoliator contributed to Amber's arrhythmia.
The inquest in Pontypridd heard Amber died at the University Hospital of Wales in Cardiff on December 5.
