This was one of the key findings of GreenCape's Water: Market Intelligence Report 2017 which was released on Thursday.
In a statement, economic opportunities MEC Alan Winde said the report provides a detailed overview on water usage and projections of demand.
"Apart from us all playing a role in saving water, [it] also calls for innovative approaches from the public and private sector," Winde said.
On Monday the City of Cape Town said the city has enough water stored for another 121 days. Residents are currently facing Level 3B water restrictions for the first time. These limit the use of potable water.