Cape Town's aquifers: Cape Flats, Table Mountain Group and Atlantis
Under and around Cape Town are three aquifers, rock and sand that hold water underground. The City is pumping more from them so it relies less on the dams.
Updated 4 November 2026
Atlantis
The sandy Atlantis aquifer on the West Coast covers about 250 km² and has supplied Atlantis with groundwater since the 1970s. It supplies between 5 and 9 million litres of drinking water a day, and the City expects upgrades to raise that to about 25 million.
Treated wastewater and stormwater are fed back into the ground through recharge basins, to keep the aquifer topped up.
Cape Flats
The Cape Flats aquifer stretches over about 400 km², from False Bay to Brackenfell and Milnerton. Five groups of boreholes pipe water straight to the nearest treatment plant, and the City planned for them to produce about 50 million litres a day.
To stop the aquifer being drawn down too far, the City plans to recharge it with treated water, a process called managed aquifer recharge.
Table Mountain Group
The Table Mountain Group aquifer is the biggest of the three, about 11 000 km² stretching from Vanrhynsdorp to Cape Agulhas and Gqeberha, including the mountains around the dams.
Eight boreholes into its Nardouw layer have pumped into Upper Steenbras Dam since August 2020, about 15 to 17 million litres a day. A second wellfield in the Peninsula layer is meant to bring that to about 25 million, and the City aims for about 50 million litres a day from the aquifer in all.
How much it adds up to
The City plans for about 7% of its water to come from groundwater by 2040. Every borehole needs a water use licence from the national Department of Water and Sanitation, which sets how much can be pumped so the aquifers aren't run down.