Medecins Sans Frontieres says that cholera is spreading to remote rural areas and starting to decline in some centres such as Harare.
The UN says at least 2,755 people have now died - a 20% rise in a week.
The rainy season could lead to even more infections, as water sources become contaminated, aid workers warn. MSF Zimbabwe representative Manuel Lopez said that small villages off the main roads were now being affected following the Christmas holidays, when urban residents went home.
Funerals of cholera victims had also seen the infection spread out of the cities. This is because bodies are not disinfected before burial and the disease spreads as people handle the body.
The cholera outbreak has been fuelled by the collapse of Zimbabwe's health, water and sanitation systems.
