Cleveland Dodd was found unresponsive in the early hours of October 12, 2023 inside his cell in Unit 18 at Perth's Casuarina Prison, becoming the first juvenile to die in detention in Western Australia.
The 16-year-old had made eight threats to self-harm and numerous requests for medical treatment in the hours before he was discovered and taken to hospital.
He died eight days later.
Coroner Philip Urquhart on Friday shared his preliminary observations as part one of the inquest came to a close, following more than a week of evidence that he said "breached" the unit's closed doors.
The coroner said the unit, inside a maximum-security prison built for adults, was unfit for housing youth detainees and they could not be treated in a way that reflected the community's values.
He also raised concerns about the system for monitoring detainees deemed to be at risk of harming themselves and said there was serious doubt it could be done in Unit 18.
"Unlivable, disgusting and inhumane, just three descriptions of the conditions of cells at Unit 18 by 2023," he said.
"What also concerns me is that many of these cells had no running water not just for the odd day, or odd hour but lengthy periods of time."
Mr Urquhart also noted evidence about the lack of staff training and junior staff filling senior roles, along with the extensive use of confinement that resulted in some detainees spending more than 20 hours per day in their cells.
"The evidence again coming to me is that it wasn't just on the odd occasion," he said.
"It was day in, day out and on some of the evidence week in and week out."
The coroner also put the Department of Justice on notice and told the court it had failed to provide requested information.
He read out a series of questions he wants answers to before the inquest resumes on July 22, including how it is that Unit 18 was chosen as a place to house children.
"This is the end of part one of the inquest but it's only just begun," he said.
"We have so much more to look at and I will do my very best to find answers."
An inquest has heard Cleveland Dodd had asked for water before he harmed himself. (HANDOUT/SUPPLIED)
The inquest also heard that every Unit 18 cell had damage that detainees could have used to inflict injuries on themselves.
A damaged air vent in the ceiling has been linked to Cleveland's fatal injury.
The unit's management team was aware of the damage and it was scheduled for repair on October 11, but that didn't happen.
Mr Urquhart said he inspected Unit 18 after the teen died and found damage to the air vents in seven of the 16 cells he examined.
The inquest has been told other cells had exposed wiring and broken plumbing, and were filthy.
Cleveland's cell had no running water and he also made multiple calls from his cell in an agitated state asking for drinking water, before he was found motionless.
The inquest has heard night shift staff ignored those requests because a senior officer had informed them Cleveland had been given six cups of water with his dinner and his cell was not to be unlocked.
But CCTV footage shows Cleveland was given only three cups of water when his evening meal was delivered to his cell about 6pm, along with a bladder of milk.
Cleveland's threats to self-harm on October 11 and 12 started after his fifth request for water was ignored.
The United Nations stipulates "drinking water shall be available to every prisoner whenever he or she needs it".
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