The City of Cape Town’s R5.2 billion upgrade of the Potsdam Wastewater Treatment Works (WWTW) in Milnerton has passed the halfway mark, with construction now 60% complete and on track for its 2027 completion date.
Launched in April 2023, the project is the largest wastewater infrastructure investment in the Western Cape and will double Potsdam’s treatment capacity from 47 million litres to 100 million litres per day. Once fully operational, it will improve the quality of treated water released into the Diep River—which flows into the Milnerton Lagoon—and significantly expand the supply of high-quality effluent available for reuse by businesses, farmers, and recreational users.
Key progress achieved includes the ultrafiltration plant, which entered a 12-month trial period in June 2025. New technologies such as micro-screening, ultrafiltration membranes, and ultraviolet disinfection are being tested to raise water quality standards before release into the environment. The treated effluent pump station has also been completed, with final pressure testing and connections underway. Once online, end-users in Milnerton, Century City and surrounding areas will be able to draw treated water for irrigation and industrial use. In addition, the dewatering plant has been operational since May 2025, with trial operations scheduled to conclude in October 2026. Early results show improvements in biological stability and reductions in solids during treatment.
“We are future-proofing our city by investing in infrastructure at a rate far outpacing any other metro. Over the next three years, Cape Town will invest R16.4 billion in Water and Sanitation—more than Johannesburg and Durban combined,” said Councillor Zahid Badroodien, Mayoral Committee Member for Water and Sanitation.
He noted that achieving two-thirds completion of a multi-billion-rand project on schedule was a major milestone that demonstrates the City’s commitment to timely delivery and long-term quality standards.
The upgrades are also designed to solve persistent issues, including inflows that exceed current design capacity and sand ingress caused by sewer collapses. Major elements still under construction include new inlet works, a membrane bioreactor (MBR) treatment module, a raw sewage pump station, and a process control facility—all scheduled for completion by late 2027.
Restoring the health of the Milnerton Lagoon remains a core priority. “Improving the quality of water flowing into the catchment is a top priority for the City,” Badroodien added.
