Water Engineer Restores Safe Drinking Water, Preventing Cholera Outbreak in Cape Town

The moment

In March 2023, as Cape Town grappled with the aftermath of a severe cyclone, the city’s informal settlements faced a mounting crisis. Torrential rains had unleashed flooding that damaged critical infrastructure, including water pipelines and sanitation facilities. Displaced residents, many living in densely packed, makeshift dwellings, suddenly found themselves without reliable access to clean water. Reports of increasing gastrointestinal illnesses prompted urgent concern from local health authorities and aid agencies alike. In this context, Zahra Nkosi, a water-sanitation engineer with over a decade of field experience, arrived on-site to assess and respond to the rapidly evolving emergency. Her task: to stem the risk of a waterborne disease outbreak by restoring safe drinking water to affected communities.

Why years of experience made the difference

Zahra’s extensive background in emergency water systems management had prepared her to navigate complex, high-pressure situations with technical precision. Over her 12 years of fieldwork across diverse humanitarian settings, she had developed a nuanced understanding of pipeline failure modes, disinfection procedures, and system resilience strategies. Unlike less experienced responders who might rely solely on standard protocols, Zahra’s expertise allowed her to interpret real-time data and adapt her approach accordingly.

One of the key skills she brought was proficiency with rapid damage assessment techniques. Her familiarity with portable pressure gauges enabled her to perform pressure testing along several sections of the compromised pipeline network. These tests involve measuring pressure drops to identify leaks or blockages, a process that requires understanding the typical pressure ranges for different pipe materials and configurations. Additionally, Zahra employed dye tracing—injecting biodegradable, non-toxic dye into suspected leak points and observing its emergence at other locations—to precisely localize pipeline breaches. This combination of methods, honed through years of field practice, allowed her to avoid the time-consuming process of blind excavation and instead focus repair efforts where they were most needed.

Her knowledge of WHO-recommended emergency chlorination practices was equally critical. She understood that simply adding disinfectant was insufficient without proper dosing, contact time, and residual management. Her experience with portable chlorination units—compact devices that deliver precise doses of sodium hypochlorite—permitted rapid deployment in the field. Zahra also recognized the importance of infection control standards, ensuring that disinfection procedures minimized recontamination risks while safeguarding both the community and her team.

What happened next

Using pressure gauges, Zahra quickly mapped the pipeline system’s integrity, identifying several critical leaks located near the most densely populated zones. She coordinated with logistics teams to ensure the delivery of replacement pipes, fittings, and repair materials directly to these points. While waiting for physical repairs, Zahra deployed portable chlorination units to disinfect the contaminated water sources on-site. She calculated the appropriate chlorine dose based on water volume, flow rate, and contact time, adhering strictly to WHO guidelines to achieve effective disinfection.

Her team performed temporary repairs to re-establish water flow, prioritising the most critical segments first to restore supply to the largest number of households. Once flow was restored, she conducted water sampling and residual chlorine testing to confirm the safety of the water. Within 48 hours, her team had successfully restored safe drinking water to over 1,000 households in the affected settlements. The rapid intervention prevented the likely escalation of cholera and other waterborne diseases, which had been a genuine threat given the contaminated infrastructure and vulnerable population.

Throughout the operation, Zahra maintained close communication with local health authorities, providing updates on water quality and system status. She also documented the technical procedures and lessons learned to inform future emergency responses. Her precise assessments and targeted repairs minimized resource wastage and ensured that interventions were both effective and sustainable within the emergency context.

What this tells us

This case exemplifies how deep technical expertise in emergency water systems management directly translates into life-saving actions. Zahra’s ability to interpret complex system failures, select appropriate disinfection protocols, and execute targeted repairs exemplifies the importance of specialised knowledge in humanitarian aid. It underscores that rapid, informed decision-making—rooted in practical experience—can prevent disease outbreaks, preserve public trust, and optimise resource use in crisis settings.