bottom and top 10% observations, WTP range from 0.36 to 19.4% of daily GDP per hour of electricity unserved. We disregard many important dimensions, assuming that the WTP of an individual to prevent power outage is proportional to GDP per capita in the country and disregarding the dependency of this WTP to the frequency and duration of power outages. This leads to underestimating the cost in countries with few and short outages and overestimating it in countries with many and long outages. We then use the data from the annual Doing Business survey<sup>6</sup> to estimate the duration of outages in 139 countries, leading to the estimate between 0.002 and 0.15% of global GDP. For reference, the cost of power outages would be valued at 0.001% of global GDP (USD 1.3 billion per year) if non-served electricity was priced with electricity tariffs, and at 0.007% of global GDP (USD 9 billion per year) if GDP per hour was used to value one hour of power outage.

This cost of power disruption underestimates the real impact on the well-being of households. First, there is a large uncertainty in the estimates of people’s WTP to prevent power outage, and it is unclear whether they include all relevant components, and in particular health effects, impacts through jobs and salaries, cost of generators, etc. In particular, electricity outages have a significant and large impact on firms’ output, what indirectly decrease household’s wellbeing through wage reduction (Rentschler et al., 2019b). However, it is likely that such an indirect impact is disregarded or underestimated in household’s monetization of lost utility. Moreover, it is unclear whether households consider their generator as a sunk cost: once the up-front cost of the generator is paid, there is little incentive for household to pay for service improvement, possibly reducing the WTP. Second, the Doing Business survey is considering outages for the average firm in the capital city, possibly leading to a large underestimation of the number and magnitude of disruptions. Moreover, not all countries are included in the Doing Business survey and the missing countries are mostly in the bottom 50% of the GDP per capita distribution, and therefore the most likely to experience numerous outages (Figure 1). This would increase the likelihood of underestimating the cost of outages. Finally, using a WTP to estimate the well-being impact of power outage creates a strong bias against the poorest. Since these disruptions affect mostly people in poor countries where WTP are mechanically low – due to the wealth effect –, the impact expressed in dollars may appear small, hiding significant implication for immediate well-being, but also for the ability of households to prosper and escape poverty.

# 2. The impact of water disruptions

## 2.1. Water disruptions have a strong impact on health

The few studies focusing on health impacts of water provision disruptions and dysfunctions consistently show negative effects on health due to water disruption episodes (Figure 5)<sup>7</sup> . Water outages can affect health through a number of different channels. Disruptions may force households to use unsafe alternative water sources. It may also affect household hygiene practices. Water disruptions (including low-pressure episodes) may increase risk of water supply contamination, what affects consumption once water is accessible again. Contamination may occur if water is unsafely stored during disruptions or filtration and purification systems are malfunctioning. Most of these papers focus on systemic water intermittencies while fewer focus on one-off water disruptions.

In medium to low income countries, frequent disruptions to potable water supply are widespread (Kumpel & Nelson, 2016). From 2004 to 2013, the International Benchmarking Network (IBNET), documented

> 6 Retrieved from https://datacatalog.worldbank.org/dataset/doing-business.

> 7 Detailed numbers may be found in the Appendix (Table 6).

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