Johannesburg (CNN) -- It was midnight when a neighbor warned Freddie Ramashidza that they were in danger.
"I had just finished praying and was falling asleep. When my neighbor knocked on the door, the water was already knee-deep," he said.
Ramashidza is among thousands of people who live on a riverbank northeast of Johannesburg's center -- their homes in peril as the waters rise.
According to South Africa's government, at least 40 people have been killed across the country and more than 6,000 displaced by flooding that has submerged houses, roads and crops since December.
Officials estimate the damage to infrastructure and agricultural produce will cost the country millions of dollars, and forecasters predict more rain is on the way.
The South African Weather Service said most of the country's rivers, dams and reservoirs have reached their capacity, and any additional rainfall is expected to cause further flooding.
Meteorologists blame the downpours on La Nina, a weather pattern associated with recent wet conditions around the world.
Many of the country's poorest residents are the worst affected. On Monday, authorities evacuated more than 30 people from a shantytown in Johannesburg.
The government declared 28 municipalities in seven provinces disaster areas on Monday, meaning they qualify for federal flood relief funds.
But it could be months before the money trickles down to the people most impacted by the floods.
With more flooding likely on the way, Ramashidza said he had nowhere else to go to take cover.
'We are afraid. But there's nothing we can do," he said. "We just have to trust in God."