Mutare City Council will need $30 million to construct a new water treatment plant in Odzi to avert water shortages once suburbs that are not receiving water at the moment are connected to its system.
The city has a water deficit of 17 megalitres per day, which is expected to increase to 30 cubic metres by 2030, as demand rises.
According to the 2012 Census, Mutare had a population of 200 000, but this has grown significantly over the last eight years.
Mutare acting town clerk Dr Anthony Mutara said the new treatment plant would draw water from Osbourne dam or Pungwe River.
"A study commissioned in 2010 indicated that we would need water augmentation to the city owing to the growth of the population against the demand for water," he said.
"This deficit is not visible at the moment because the supply to areas like Dangamvura is limited, but the moment we finish the Dangamvura pipeline project and start supplying water to those areas, we will begin to see the deficit," he said.
Mutare city currently draws water from Pungwe River, Odzani and Small bridge dams and Osbourne Dam will be the most likely water source for the new treatment plant.
Dr Mutara said the city could also get more water from the Pungwe River, but the local authority would have to engage its Mozambican counterpart to get access.
Pungwe River flows from Zimbabwe into Mozambique and drains into the Indian Ocean and Mutare and the city of Beira get water supply through an inter-city catchment transfer facility where the amount each city draws from the river is limited.
He said the plant needed to be constructed with speed as Dangamvura was expected to start receiving water supply as soon as the new pipeline project is complete.