When an Algorithm Cuts Off Your Water, Who Owes You a Reason?
A High Court has ruled that a monitoring system is not evidence until someone can explain how it works and whether its reading is right.
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A butchery in Komga ran its lights on solar for a year. In February, the Great Kei municipality cut off its grid supply without notice, flagged by a monitoring system that saw no electricity purchases. On 14 October 2025, the Eastern Cape High Court declared the disconnection unlawful, struck down part of the credit control policy as unconstitutional, and asked the municipality a question most municipal managers in South Africa cannot yet answer. How does the monitoring system work, who is qualified to interpret it, and what evidence do you have that it got this one right? When an algorithm cuts off a resident’s water, somebody still owes them a reason.
CONTEXT AND BACKGROUND
The Trendigraph CC v Great Kei Local Municipality judgment is the first direct ruling by a South African court on the kind of monitoring that now underlies most municipal credit control. Judge Laing found the municipality had no factual basis to disconnect, filed no affidavit from the provider of its monitoring system, and could not show that its own staff were qualified to interpret the data. He declared parts of the credit control policy unconstitutional for allowing disconnection without the adequate prior notice required by section 3 of the Promotion of Administrative Justice Act.
The judgment builds on a Constitutional Court foundation most municipal officers already know by name but have not yet reread. In Joseph v City of Johannesburg, the court held that providing municipal services creates a public-law relationship, with procedural fairness owed to the citizen before service is terminated. What Trendigraph adds is that this duty now applies to decisions driven by automated systems whose logic the municipality cannot explain.
INSIGHT AND ANALYSIS
The exposure is not confined to the Eastern Cape. The City of Johannesburg itself admits that it bills households for water they did not receive, estimates consumption for months at a time, and receives sixteen thousand billing queries a month across 1.2 million accounts. A homeowner in Dainfern has received a R2.9 million water bill based on recorded consumption of nearly six thousand kilolitres in a single month, and the City requires a fifty per cent upfront payment before formal dispute resolution.
The direction of travel is confirmed by a parallel ruling. In January 2025, the High Court struck down regulations that let the South African Social Security Agency use automated bank and database checks to decide who received a Social Relief of Distress grant. The grant decision and the water cut-off are the same category of administrative action. Every municipal credit control policy that relies on automated flagging is one urgent application away from the same declaration of unconstitutionality.
I have previously written about who the law looks for when AI gets it wrong, arguing that the algorithm is not the legal actor and that accountability falls on the human who relied on it. For a municipality, that human is the municipal manager. The computer cannot stand in court. The vendor cannot be summoned. The person who delegated the decision to the software is the person who must give the reason.
IMPLICATIONS
Three questions follow for every municipal manager. Who in my organisation can explain, in writing, why a specific household was flagged for disconnection last week? What record exists of the human decision that signed off that flag before the notice was issued? What appeal path has the household been given before the lawyer they cannot afford has to approach the High Court? If the answers do not exist, the municipality has a legal exposure, not a technical problem.
For a chief financial officer, the exposure is specific and growing. Trendigraph received a scale C costs order. A city that must defend thousands of individual decisions it cannot explain faces a litigation bill its credit control software was meant to prevent.
CLOSING TAKEAWAY
When an algorithm cuts off your water, somebody owes you a reason. South African law has now made it clear who. It is not the algorithm, which cannot speak. It is not the vendor, which is not a party to the public-law relationship. It is the municipal manager, who signed off on a credit control policy that delegated a constitutional duty to a system whose logic they cannot explain. Automation is permitted. Accountability is not. A municipality can automate the decision. It cannot automate the reason.
Johan Steyn is a prominent AI thought leader, speaker, and author with a deep understanding of artificial intelligence’s impact on business and society. He is passionate about ethical AI development and its role in shaping a better future. Find out more about Johan’s work at https://www.aiforbusiness.net
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