The Australian state of Queensland is facing a reconstruction task of "post-war proportions", as floods left swathes of it under water.
State Premier Anna Bligh said the state was reeling from the worst natural disaster in its history.
Powerful flood waters have surged through the state capital, Brisbane, leaving thousands of homes submerged.
The floods peaked at a lower level than expected but more than 30 suburbs are under water.
Huge amounts of debris - cars, boats and jetties - have been floating downstream, some smashing into bridges.
One man died when he was sucked into a storm drain and two more deaths elsewhere were reported by Australian broadcaster ABC, bringing the toll from this week's flooding to 15, with dozens more missing.
The Brisbane River is now receding and was expected to fall to around 3.2m by early on Friday.
It peaked at 4.46m (14.6ft) just before 0530 (1930 GMT Wednesday), short of the 5.4m (17.7ft) in the 1974 floods.
West of Brisbane, the small town of Goondiwindi is on high alert, with fears the flooding Macintyre River could swamp the town.
Police are continuing to search areas of the Lockyer Valley for those missing after a torrent of water swept through the area on Monday.
"Queensland is reeling this morning from the worst natural disaster in our history and possibly in the history of our nation," Ms Bligh told reporters.
"We've seen three-quarters of our state having experienced the devastation of raging flood waters and we now face a reconstruction task of post-war proportions."
In Brisbane, the worst-hit suburbs included Brisbane City, St Lucia, West End, Rocklea and Graceville.
"There will be some people that will go into their homes that will find them to be never habitable again," Ms Bligh said.
Brisbane Mayor Campbell Newman said 11,900 homes and 2,500 businesses had been completely flooded, with 14,700 houses and 2,500 businesses partially submerged.
Milton resident Brenton Ward reached his home in the suburbs by rowing boat.
"We have water to the waist in the living room. We have to check the amount of damage - probably (the) electricity has to be all rebuilt," he said.
Other residents said they felt lucky.
"I can handle this," said Lisa Sully, who had some flood damage to her home in the suburb of Sherwood. "Mentally, I was prepared for worse."
Many supermarkets in the city have been stripped of supplies, while a number of rubbish collections and bus services have halted. More than 100,000 properties had their power cut to reduce the risk of electrocution.
Where waters had receded in the city centre, sticky mud remained. Officials said the clean-up could take months.
Brisbane airport survived the swell and remains open, with almost all flights unaffected. However, passengers are advised to check before travel. Public transport to the airport is severely limited.
Extra police have been brought in to patrol the city.
The man who died was a 24-year-old who had gone to check on his father's property and was sucked into a storm drain.
The bodies of two victims of floods earlier this week were also found, one in the Lockyer Valley and the other in Dalby, ABC said.
Sixty-one people are still missing, with police very concerned about 12 people in the Lockyer Valley not seen since their homes were destroyed by a wall of water on Monday.
More rain caused by a cyclone off the Queensland coast is forecast for the next two days.
The weeks of rain have been blamed on a La Nina weather pattern in the Pacific.