Authorities are confident the River Murray flooding has reached its peak in Renmark Tuesday night, with about 1,700 to 1,800 properties inundated so far.
South Australian Premier Peter Malinauskas said passing the peak was good news for the town.
"The peak has now occurred here at Renmark, we've had five consecutive days where the flows coming across the border have actually declined and overnight we saw the water level here at Renmark drop for the first time here in a long time," he said.
The peak is expected to reach Berri in the next couple of days.
Mr Malinauskas said there was "still a challenge in front of us" as the peak moved slowly through communities along the River Murray.
"None of its going to be easy, but when we work together we can achieve a lot," he said.
On Wednesday, Mr Malinauskas told ABC Radio Adelaide that the river flows had peaked at Renmark between 185 and 190 gigalitres.
"Normally, at this time of the year we'd see an on average flow of around about 15 to 17 gigalitres a day," he said.
"So, even if it goes from 190 gigalitres down to 150, we're still ten times the average.
"So, it's a lot of water, and we've got a journey in front of us but largely I think communities across the area have responded exceedingly well."
SA State Emergency Service Chief Officer Chris Beattie said flows at the border were now 175 gigalitres.
Mr Beattie said the Renmark council would be "breathing a bit of a sigh of relief in terms of the peak passing".
"But the threat hasn't subsided yet," he said.
"Those levees are still under load, there's still a lot of places that are inundated and flooded and we still have those hazards in the river particularly with respect to power infrastructure and that other infrastructure like bridges where there's a material risk to people if they're not heeding the warnings," he said.
Mr Beattie said about 1,700 to 1,800 properties across the Riverland had been inundated so far.
Evacuation warning for Cowirra
Meanwhile, a flood emergency warning has been issued for Cowirra, in South Australia's Murraylands, with people urged to evacuate.
The State Emergency Service (SES) said flooding was expected to cause isolation to properties within 24 hours due to the deterioration and flooding of East Front Road and Hunter Road at Cowirra, opposite Mannum.
The SES said there was a chance properties may also become flooded, and urged residents to evacuate now if the path was clear to a safer place.
Those unable to find alternate accommodation can attend the emergency relief centre at the Mannum Football Club on Belvedere Avenue.
The Department of Transport said a free passenger ferry service between Cowirra and Mannum – which only began operating on Tuesday – will close until further notice from this afternoon due to the closure of the Burdett and Hunter roads junction at Mannum.
The Wellington ferry will also close due to rising water levels.
