Cholera, which brings on diarrhoea that can fast lead to severe dehydration and death, is preventable and treatable under normal circumstances.
But Zimbabwe's health sector is collapsing, with not enough money to pay for essential resources, while doctors and nurses often strike over pay.
A political crisis and economic meltdown have left the water-delivery system in disarray, forcing residents to drink from contaminated wells and streams.
Harare residents suffered a crippling 48 hour water cut, after the state-run water company ran short of aluminium sulphate, a chemical used to purify water, on Saturday.
Water was mostly restored in the capital on Wednesday, according to Walter Mzembi, the water resources deputy minister.
But Mzembi warned his ministry only had water treatment chemicals to last about 12 weeks, and called for donor support, the Herald reported.
"I am appealing for at least 40 million rand [$3.89m] to purchase chemicals for the next two months and the money is needed between now and next Monday," The Herald quoted him as saying.
The Zimbabwe government also appealed for $450m in aid to deal with food shortages.
Charities have warned that the cholera outbreak has already spread to neighbouring South Africa.
Health authorities in northern South Africa said the Limpopo River, a major waterway and border with Zimbabwe, had tested positive for cholera this week.
Zimbabwe is suffering the world's highest inflation, officially estimated at 231 million per cent, unemployment of more than 80 per cent and dire food, water and fuel shortages.
Critics blame the crisis on the policies of Robert Mugabe, Zimbabwe's president, and the situation has worsened amid a stalemate in power-sharing talks with the rivals over cabinet positions.
Western governments have shunned Mugabe's government and subsequently cut back on aid to the country.