Crown prosecutor Edward Fleetwood said Kornaus was visiting a friend at Vicinity Apartments in Woolloongabba on February 19, 2021.
After 2am the next day, fireys were called after reports of water inexplicably flowing into the elevators.
The court was told Kornaus had been captured on CCTV opening fire hydrants in the stairwells on floors six and seven.
Fleetwood said this activated diesel pumps, which pumped about 1000 litres of water per minute through the building – all the way down to the ground floor.
“The water flowed unabated for approximately 30 minutes before being turned off,” he said.
About half the units in the building were impacted, forcing residents to leave.
“Electricity was restricted and elevators couldn’t be used for some time,” Fleetwood said.
“The damage was in excess of $500,000 and the body corporate was approximately $10,000 out of pocket.”
Kornaus also removed fire extinguishers in the complex along with signs showing where the apparatuses were located.He used one extinguisher to randomly hit a parked car.
“It’s clearly a drunken episode of stupidity which got out of control,” District Court Judge Michael Byrne said.
Kornaus pleaded guilty to a raft of charges that included interfering with fire apparatuses, entering premises committing an indictable offence and wilful damage.
He also pleaded guilty to contravening a police direction when he refused to give attending officers his name and address.
Boddice said his client did not foresee the extent of the damage he would cause by opening the extinguishers.
Kornaus, who had previously been diagnosed with autism and a non-verbal learning disorder, has since penned a letter of apology indicating remorse for his actions.
The court was told he struggled with alcohol addiction and was “blackout drunk” on the night of the offence.
“He acknowledges he can’t do it in moderation … he’s come to the conclusion it’s just not for him,” Boddice told the court.
Judge Byrne sentenced Kornaus to 18 months’ jail but wholly suspended the sentence.
He also imposed a two-year probation order.