Flooding-driven sanitation failure and enteric disease risk in urban informal settlements: Cholera as an illustrative case for climate-resilient sanitation in low- and middle-income countries

Abstract

Climate change is intensifying rainfall extremes and urban flooding, amplifying public health risks in settings with fragile sanitation and drainage systems. In dense urban informal settlements, floods can overwhelm onsite sanitation and fecal sludge management systems, causing pit inundation, latrine overflow or collapse, and contamination of household environments and water sources. These conditions increase fecal exposure and can amplify cholera risk, particularly where water supply is intermittent and households depend on unsafe sources. Using Lusaka, Zambia as an illustrative case, this essay illustrates flood-driven sanitation failure modes and the feedback loops that can sustain exposure and delay recovery. Lessons from prolonged cholera epidemics in fragile water and sanitation settings underscore that emergency response tools can suppress transmission, but long-term durability depends on sustained investment in safe water and sanitation services and reliable surveillance. Building on recent calls for climate-resilient sanitation, this essay frames sanitation functionality during floods as a core component of epidemic preparedness in LMIC cities, with priorities including flood-resilient containment and fecal sludge services, management of shared sanitation facilities (clear responsibility, cleaning and maintenance systems), routine maintenance and supply-chain reliability, community-engaged early warning and response, and monitoring systems that link service and environmental indicators to health outcomes.