Costs of increasing climate resilience for urban water supply and wastewater services in low- and middle-income countries

Climate projections indicate the incidence of droughts and floods will progressively increase in many world regions during the next century. As the impact is increasingly felt by urban populations, national and municipal authorities must plan to ensure the resilience of water and wastewater infrastructure. This requires information on how much it costs to close service gaps, and the additional costs of assuring resilient services. This paper estimates the costs of extending water and wastewater coverage to urban populations in 131 low- and middle-income countries (LMICs), and the costs of protecting populations from flood and drought risks under different climate scenarios and target years. The estimates draw on service coverage data from the United Nations and cost data from published studies and data sets. Annual costs of achieving universal access to safely managed water supply in urban areas in 131 LMICs by 2040 are US$21.78 billion (US$8.6 billion capital and US$13.1 billion operation and maintenance – O&M), equivalent to US$5.5 annually per capita. Under Shared Socioeconomic Pathway 3 (SSP3), annual cost of achieving greater resilience is US$2.46 billion (droughts) and US$99 million (floods), with a total of US$2.55 billion representing an increase of 12% over the baseline costs. The cost of increasing wastewater treatment to 100% coverage for those connected is $46.4 billion per year, while the cost of extending wastewater services to the unserved and making wastewater services climate resilient is $44.6 billion per year, representing a 96% increase. This study concludes that the greatest financial challenge remains achieving universal coverage of safely managed water and wastewater services. However, budgeted plans should incorporate climate resilience to improve service continuity and prevent costly repairs and retrofitting infrastructure in the event of climate events.