The City of Cape Town has attributed the drop in dam levels in the past week partly to hot weather and winds.
In its latest water update‚ the city said dam storage levels were at 36.8%, but the last 10% is not usable.
"Our dam levels have declined by 1% over the past week. This could be attributed to the high winds and hot weather, which contributed to evaporation‚" mayor Patricia de Lille said in a statement.
She said the city had managed to halve its water usage thanks to the efforts of 51% of the city’s water users.
"We will only get through this crisis together. To make this partnership work even more effectively‚ I appeal to all water users‚ especially the 49% who are not saving water yet‚ to join us all as we escalate efforts to beat this drought‚" De Lille said.
She urged all the city’s water users to "come on board with Team Cape Town" as the city expects a steady decline due to the heat and wind expected in summer.
"We need to do more to bring our usage down while at the same time pulling out all of the stops to ensure that we implement various projects for additional water supply to help see us through to winter 2018‚" De Lille said.
Her statement comes amid the fear that the city might run out of water due to the worst drought in the past 100 years.
The whole of the Western Cape has been declared a disaster area‚ with towns like Beaufort West edging closer to running out of water completely.
Currently‚ the city is working on water augmentation projects‚ which include desalination‚ groundwater extraction and water reuse.
But there is concern about whether the city will have its projects up and running by the time its dams run dry.