Kinshasa is crisscrossed with small rivers and waterways, which often double as open sewers. Many have now overflown.
The Congo River basin floods every year between December and mid-January, according to RVF director Daniel Lwaboshi.
Burst riverbanks are causing turmoil in DR Congo's capital Kinshasa, with dark and foul-smelling water pouring into homes across working-class neighbourhoods in the central African megacity.
The metropolis of some 15 million people sits on the Congo River -- the second largest in Africa after the Nile -- which has swollen to near-record levels over the past several weeks.
Kinshasa is crisscrossed with small rivers and waterways, which often double as open sewers. Many have now overflown.
In the district of Pompage, a bridge over one such small river has been completely submerged, creating a stinking and stagnant pool in the middle of a residential district.
"The river is backing up," said Therese Matete, a 45-year-old seller of dried fish, pointing to a body of water, covered with plastic bottles.
In lieu of the bridge, residents now have to use a makeshift canoe pushed by young men waist-deep in the water. The fare is 500 Congolese francs ($0.19, 0.17 euro cents).
Niclette Luzolo, a 32-year-old hairdresser in Pompage, said her house had completely flooded.
"Everything's destroyed, we've got nothing left. I'm sleeping in church with my four children and the mosquitoes are biting us," she said.
Flooding is common in the Democratic Republic of Congo's capital, but locals say that this year is the worst.
In late December, the agency that manages the DRC's waterways, the RVF, warned of "exceptional flooding" along the Congo River and its tributaries.
Measurements taken in Kinshasa indicated that the river had risen 5.94 metres (19.5 feet), close to the high-water mark of 6.26 metres during record flooding in 1961.
 'The hand of man'Â
The Congo River basin floods every year between December and mid-January, according to RVF director Daniel Lwaboshi.
Water levels normally rise about five metres, he said, but the current levels have been high enough to submerge most of the quays and ports along the river.
This prevents boats from docking and goods from moving between the capital and the interior of the country, which is mostly only accessible by river or air.
Lwaboshi gestured out of his window, to the RVF courtyard strewn with aquatic plants brought by recent flooding. A small crocodile even ventured into the courtyard, he said.
The director said that heavier downpours, linked to climate change, in part led to the exceptionally high river.
But "the hand of man" is also involved, he said, explaining that deforestation hardens the earth and makes it less absorbent of water.
Runaway construction in floodplains in overcrowded cities such as Kinshasa also play a role, Lwaboshi added.
Modern developments, nevertheless, appear to be just as affected.
Kinshasa's Cite du Fleuve, a new neighbourhood vaunted as state-of-the-art, has flooded, for instance.
In another part of the city, river waters have seeped into the building sites of unfinished luxury villas.
"There's a lot of work to do," said Lwaboshi. "Future generations will have to pay a heavy price for our mistakes".
Underwater TintinÂ
It is not clear how many people have been affected by the floods in the DRC, but it is thought to be in the hundreds of thousands.
On January 6, the Catholic charity Caritas appealed for help for about 100,000 households in Mbandaka, a riverside city some 600 kilometres (370 miles) northwest of Kinshasa.
Further upstream, in the city of Kisangani, the mayor said that over 200 houses have been submerged in one district.
Waters should begin to recede in several days, with the onset of a short dry season, Lwaboshi of the DRC's river agency said.
The waterline should return to normal by February.
"That's when we'll be able to see the damage," he said.
In Kinshasa's Kinsuka district, Deborah Zu, the manager of popular riverside eatery Chez Tintin, said she was pleased that her father, who founded the establishment, had chosen to build on the high ground on the advice of neighbours who remembered the 1961 flood.
But the river has risen higher than ever this year, spilling into the restaurant and the car park -- even submerging a statue of the eatery's cartoon character namesake.
In early January, only Tintin's famous quiff of yellow hair was poking above the water line.