Little baby Alex McCartney was in the bath with his two-year-old sister when his mother, Joanne Pedlow, 33, popped downstairs.
The baby and his toddler sister were in just five inches of bath water, and Alex was in a purpose-built seat, attached to the bath by four suction cups.
Mum Joanne took a little while longer downstairs to let family members in, and that short time was all it took for Alex to drown in the bath.
When she returned upstairs with the other family members, alerted by her two-year-old daughter's cries, they found Alex face down in the water.
They quickly called an ambulance and Alex was taken to the hospital. He survived for four days on life support but died almost immediately after they decided to remove his breathing tube, in January last year.
According to hospital officials, he suffered a brain injury as a result of being submerged in bath water and also developed pneumonia because of life support.
Now the coroner looking into his tragic death is hoping that the sad incident serves as a warning to other parents.
'Hopefully, this message will serve to spare other families the agony that this family has had to endure.'
The coroner on the case also said the incident raised an 'important learning issue' for parents and warned about the dangers of leaving a child unsupervised, even for a short period of time.
Alex's dad, Stephen McCartney, said on a Facebook post that he hopes this will 'hopefully this will prevent heart ache for other families and things like that happening again'.
Speaking of his late baby son, Mr McCartney said: 'He was such a happy wee boy. He never cried, he just laughed and smiled.
'He was at that stage where he was able to sit up – he was very strong. He liked to sit and watch whatever Lily was watching on TV.'
The NHS advice for bathing babies safely says to 'never leave your baby alone in the bath, not even for a second'.