Environmentalists and University of Zimbabwe researcher Professor Chris Magadza has partly attributed the contamination of Harare's water to the destruction of wetlands and government's failure to take protective action, while warning residents of the capital are drinking filtered urine.
Magadza made the remarks during a field trip to several Harare wetlands under threat, which include Cleveland Dam, wetlands in Msasa Industrial area, Gunhill, Borrowdale and Monavale.
Government has ignorantly dismissed preservation of wetlands as irrelevant saying the nation cannot be put to a standstill saving a "few frogs and a few trees".
Authorities controversially approved the building of a hotel and shopping mall by a Chinese company on a wetland in Monavale opposite the National Sports Stadium in Harare.
Construction is almost complete and it is already advertising shops to lease at the complex.
Magadza said without wetlands Harare's water supply was doomed, as almost all open green spaces in the city are vleis of wetlands that form the "fragile headquarters of the Manyame, Marimba, Gwebi catchment basin upon which the city is built".
He said Manyame River now supplied 50 % of clean water while the remainder was "our returned urine".
"Lake Chivero receives so much sewage and there is algae called Microcystis which can cause liver cancer," said Magadza. "For example, in South Africa this algae has killed a lot of cattle.
Water in Cleveland Dam is among the cleanest water in the country because of wetlands around the dam which clean any pollution," Magadza said.
Magadza claimed that fertilizer maker, Zimphos, produced the most pollution that finds its way into Cleveland Dam.
"The amount of substance found in the water in the 1960s to 1980s was around 25 microzymas, but today there is about 60-80 microzymas due to increased pollution. The acid waste from Zimphos ends up in Lake Chivero. The wetlands are an asset to water purification as they filter off fertilisers," Magadza said.
According to statistics by environmental experts, the average water table in Harare has declined from 15m to 30m in the past decade because of wetland loss and illegal sinking of boreholes.
Environmental expert Dr Willie Nduku said Harare was badly located in terms of water supply as the city was on a catchment basin yet government was allowing companies and individuals to build in areas that paused threats to the city's water sources.
Harare Residents Trust chairperson Precious Shumba said the local authority was not committed to improving water purification and supply although pre-budget consultations indicated that 58% of the US$64 million collected by the Harare City Council up to the end of July this year was from water bills.
"From our analysis of the revenues being collected by the city, the bulk of the money is coming from the water services, confirming that water is the council's cash-cow, which has reportedly financed most council operations, including payment of salaries and administration costs," said Shumba.
"But there has not been any meaningful investment of the revenues collected from water services into infrastructure development and expansion."