This article investigates the effects that attacks during armed conflict which damage water and wastewater services have on the outbreak and transmission of infectious disease. It employs a lens of uncertainty to assess the level of knowledge about the reverberations along this consequential chain and to discuss the relevance to military planning and targeting processes, and to the laws of armed conflict. It draws on data in policy reports and research from a wide variety of contexts, and evidence from protracted armed conflicts in Iraq, Yemen and Gaza. The review finds a strong base of evidence of the impact of attacks on water and wastewater services, and a high level of confidence in information about the transmission of infectious disease. One clear risk identified is when people are exposed to water supplies which are contaminated by untreated wastewater. Obtaining a similar level of confidence about the cause and effect along the full consequential chain is challenged by numerous compounding variables, though there are a number of patterns related to the duration of the armed conflict within which the attacks occur. As the conflict protracts, both the risk of the spread of infectious disease and the evidence base for gauging the reverberating effects becomes stronger, for example. The article concludes that the reverberating effects of damage from an attack can be foreseen in some contexts and can be expected to become more foreseeable over time. The analysis suggests that the most pragmatic path for military institutions and those involved in targeting operations to take this knowledge into account is through a “precautionary approach” which assumes the existence of the reverberating effects, and works them in to the standard information-gathering and planning processes.

This article reviews the factors that determine the impact of explosive weapons on urban services in space and time, with a focus on drinking water services. The evidence comes from published and unpublished research and records, as well as experience restoring or maintaining such services. Urban services are seen as interconnected, and each composed of interdependent components of people, consumables and hardware. Elements that make up the components are labelled “upstream”, “midstream” and “downstream”, to reflect their location and hierarchy in the production and delivery of any urban service. The impact of explosive weapons is broken into the direct effects on any of the components of a service, and the reverberating effects on up- and or downstream components of the same service, or on other services. The effects are most commonly observed in service infrastructure, and determined chiefly by the extent of the damage to the functionality of any component. The spatial extent of the impact is found to be determined primarily by the hierarchy of the component suffering the direct impact, with attacks on upstream components being the furthest-reaching. The duration of the impact is determined primarily by the pre-explosion “baseline resilience” of the service, itself a function of system redundancies and emergency preparedness and response. The analysis suggests that the impact is more reasonably foreseeable than may commonly be thought, in the sense that the direct effects of explosives are well known and that the most important infrastructure is generally identifiable. It follows that proportionality assessments which involve urban services would benefit from (i) the direct and consistent engagement of specialized engineers within the targeting cell, and (ii) greater familiarity of the weapons controller with services, infrastructure and systems in urban areas.