The Nelson Mandela Bay Municipality says the Metro's largest dam, the Kouga could run dry by the end of next month.
The Metro has launched a "Day Zero is looming" campaign to encourage residents to save water.
Municipal spokesperson, Mamela Ndamase says it is difficult to predict an exact date for Day Zero, but if there's no adequate rainfall and residents don't decrease consumption, it could be reached soon.
The level of the Bay's main supply dams was holding steady at just under 18% of total combined capacity last week.
The current water restrictions are 50 litres per person per day or 15-kilolitres per household per month.
Additional restrictions are still with the mayor waiting for approval.
These include the proposal to have all domestic customers to have a flow meter restrictor installed to reduce the water pressure and to reduce losses.
All domestic customers with excessive use will have a flow meter restrictor installed to limit usage to 15Kl per month.
The use of sprinklers or an irrigation system is not allowed, unless water is from a source other than the municipality.
