The city said on Tuesday that one temporary relocation area with 500 units had been established to house flood victims who wanted to be relocated.
Barry Wood, the city's manager for catchment, stormwater and river management, said a technical assessment study had identified 24 communities as hotspots, including Guguletu, Khayelitsha and Philippi.
Wood said 90 percent of in-formal settlements had floors below ground level and no conventional drainage systems.
Elizabeth Thompson, the mayoral committee member for transport, roads and stormwater, said residents should be on high alert and play their part in minimising flooding.
She appealed to residents to clear away rubbish that could block the drainage systems.
The city's Disaster Risk Management Centre also called on residents to check that their drainage systems were not blocked; to clear gutters, downpipes and furrows; to ensure that their roofs were waterproofed; and to remove dead branches from trees.
The centre added that residents in informal settlements could dig furrows around their houses to divert floods, slope their roofs to assist run-off or move to higher ground.
Residents were also advised to secure furniture that could be blown away by high winds, to be alert to weather warnings and to report blocked drains and intakes and illegal dumping.
Mzwandile Sokupa, the city's informal settlements manager, said some victims could be allocated housing units under the emergency housing programme.
But he warned that they would not be allowed to jump the province's housing waiting list, which had a backlog of 400 000 names. It was a misconception that people could skip the waiting list if they built their shacks in flood-prone areas.
The weather bureau says the province can expect short, sharp periods of rain this winter, as well as cold fronts.
Flooding, blocked drains and service disruptions can be reported to the city's all hours Technical Operations Centre on 0860 103 054.
In an emergency that threatens lives or property, contact 107 from a landline or call 021 480 7700 from a cellphone.
Meanwhile, the city says a R13.4 million investment to reduce water pressure in Cape Flats pipelines has yielded annual savings of R83m.
The project forms part of Cape Town's water demand management strategy.
Other elements of the plan include public awareness cam-paigns on water conservation, the replacement of old infrastructure and the treatment and reuse of sewage effluent.
- Cape Argus