Cape Town’s coastal water quality — the facts versus the hype

When it comes to swimming along South Africa’s almost 3,000km stretch of coastline, there is no place offering the public more transparency than Cape Town about the relative risks of coastal water quality.

The city conducts South Africa’s most robust monitoring programme across 100 nearshore sites, the results of which are all available online.

Global best practice generally entails weekly water sampling, which Cape Town has implemented at its top 30 beaches. In the case of some Blue Flag beaches, the city is even sampling daily from Monday to Friday.

The results of hundreds of samples showed consistently high water quality at designated swimming areas during the peak festive tourism period, with a full 100% of samples within recreational-use thresholds based on enterococci counts, the internationally recognised indicator for risk to human health.

All samples undergo independent analysis by a laboratory that is Sanas-accredited (South African National Accreditation System) for seawater. Cape Town’s Blue Flag beaches are also subjected to analysis by a second accredited lab under the auspices of the Wildlife and Environment Society of South Africa (Wessa), which independently confers Blue Flag status on South African beaches.

We are always at pains to point out that water sample results do not show real-time risk, but rather trends over time. The city has never claimed any coastal area to be risk-free. It has simply published water quality results that are shown to be excellent under the National Water Quality Guidelines, which state “excellent” as being less than 2.8% risk, not zero risk.

Coastal water quality is essential to Cape Town’s wellbeing and economy, and part of what makes it a special place. We want people to go out and enjoy our spectacular coastline without unnecessary fear, recognising also that there are points of pollution to avoid at known hotspots closed to recreational use, such as Lagoon Beach, Soet River mouth, and others documented by the city’s ongoing sampling and annual “Know Your Coast” reports.

Major infrastructural and societal interventions are under way to address areas of chronic pollution. General trends also show that, after rainfall flushes out catchment areas, water quality usually declines for short periods, a common phenomenon in urban areas around the world.

Where specific pollution incidents are identified, the city responds swiftly to identify the source, install warning signage, contain and clear the pollution and take samples until results show it’s safe to swim again.

This past festive season, not only did Cape Town’s top 30 beaches show excellent water quality results by global standards, the city also ensured zero sewerage-related disruptions at these recreational nodes. This responsiveness and commitment to transparency is what sets Cape Town apart as a world-class tourism destination.

Project Blue media sensation 

However, around 6 January 2025, a wave of media reporting suddenly announced to the public, in the words of one IOL report, an “alarming threat” of “widespread contamination at Cape Town’s blue flag beaches”.

In an ENCA report (since deleted), the public was told that “water experts have proof [Cape Town’s] water is not safe”, and that a report finds city officials to “have not been all that truthful about the Blue Flag status of beaches”.

Daily Maverick reported that the study – known as Project Blue – had “discredited some of the City of Cape Town’s water quality results at Blue Flag beaches”. Further, that the labs which analysed water samples had “valid” accreditation to do so from Sanas.

Media summaries prominently featured the Project Blue headline claim that “42% of sites in Table Bay and 38% of sites in False Bay exceeded guideline values”, giving the false impression that pollution is widespread across designated swimming areas along these coastlines.

These examples of salacious reporting – none of which is actually true – set off a shockwave among the beachgoing public, even as the festive season was still in full swing.

The city was flooded with queries about the Project Blue report, which had been released directly to the media and which our expert coastal management officials had not seen before.

The authors – two professors – are long-time critics of the city. Contrary to the completely false narrative of the city having “bullied” the Project Blue authors, the first action we took was to send a polite enquiry to the Rethinkthestink NPO which released the study, requesting the raw sampling data, lab sheets, and scientific references for perusal.

Even as the media hype grew, none of this information was forthcoming. However, the city did establish that:

• The labs used by Project Blue are not Sanas-accredited to analyse seawater for E. coli and enterococci, despite the report’s misleading claim that accreditation was in place. Accreditation matters, as the city’s split-testing previously showed in 2023, when the same sample sent to various labs yielded variations of over 500% in results from unaccredited labs;


• Even in the tiny dataset where Project Blue samples showed above-guideline enterococci levels at two Blue Flag beaches (one at Camps Bay, and two at Clifton), the same samples also showed extremely low E. coli levels. This is a very unusual outcome. In instances of sewage pollution, counts of these two species are almost always both elevated. The vast disparity should have been a flag for any scientist and should have drawn into question the small size of the dataset and use of a lab that is not Sanas-accredited for seawater. By contrast, the city has a huge database of recent samples (640 for Camps Bay, and 140 for Clifton) which show water quality in the good to excellent range based on the independent analysis of not one, but two correctly accredited labs;


• Contrary to media claims of widespread contamination, repeated Project Blue samples were taken at known pollution hotspots which are in fact closed to the public. This inflated the percentage of non-compliant sample outcomes, which media summaries had widely quoted to create the false impression of poor water quality at popular recreational spots open to the public;


• Despite making the claim that “for at least a decade” global best practice requires monitoring of both enterococci and E. coli in seawater, Project Blue could produce no scientific reference to support this. While this statement intended to discredit the city’s seawater sampling regime – which tests for enterococci specifically – scientific references from around the world affirm Cape Town’s approach as best practice, including the World Health Organization (2003, 2021), the United States Environmental Protection Agency (US EPA 2012), Heath Canada (2024), the New Zealand Ministry of Health (2021), and the Australian National Health and Medical Research Council (2008); and


• While not a Project Blue author, Professor Anthony Turton is quoted in the report stating that “the test protocols chosen by the (city) are inadequate in assessing the human health risks”. The city has never had an enquiry for information on its sampling regime from Prof Turton, who was clearly not aware of the extent of the city’s monitoring programme when interviewed by ENCA on 12 January.

In the interests of accurate information to the public, the city issued a release simply setting out these factual counterpoints to the media narrative around Project Blue.

This elicited a more conciliatory tone from Project Blue affiliates, who subsequently began to speak against the excesses of the media hype they had driven.

In a statement, Project Blue clarified it “has not made allegations about water quality, it has alerted city officials to the results of Project Blue”.

In the ENCA interview linked above, Prof Turton confirmed that Project Blue is “not trying to contest the credibility of city data”. Reading ENCA’s on-screen headline, Turton said “looking at your screen right now, ‘water experts have proof city’s water is not safe’ … that is not an entirely accurate representation”. He further said that “there is no dispute between us and the city, the dispute has generally been created by media type of positioning, media headlining, and what have you.”

Also on air was one of the city’s experts, Gregg Oelofse, who invited Prof Turton for a long conversation about the metro’s sampling regime, including also for marine outfalls.

At the heart of the activism behind Project Blue is a suspicion that sewage from these three outfalls – at Camps Bay, Hout Bay, and Green Point – does not disperse into a limited zone in deep waters at a safe distance from the shore as designed, without deleterious impact on the environment or human health, but instead that the pollution is carried by tides back to the beaches.

Thankfully, to debunk this fear, the city has published 10 years of extensive monitoring, reporting and analyses from independent experts, all available online, including data from hundreds of water samples from around 18 stations at each of these outfalls, which also perform salinity tests at the bottom, mid-water, and surface.

Detailed numerical dispersion modelling shows that South African Water Quality Guidelines are not exceeded anywhere along the shoreline due to the effluent from the marine outfalls.

In a first for a South African coastal city, Cape Town also has future plans to replace these outfalls with multibillion-rand wastewater treatment works and is actively conducting detailed feasibility studies in preparation to include these major infrastructure projects in its long-term financial plan.

We are also 100% on board with “citizen science” of the good faith variety, and 100% open to areas of improving our monitoring regime based on sound scientific references.

It would certainly be a net gain for accountability if the media were also to commit to refraining from spreading unnecessary alarm about the safety of designated coastal swimming areas. DM

Alderman Eddie Andrews is the city’s deputy mayor and mayoral committee member for spatial planning and the environment.