Introduction Reliable access to safe water is essential for health, economic activity, and climate resilience in small island states. In the Cook Islands, growing climate risks, infrastructure limitations, and uneven service coverage continue to challenge water security, particularly in the outer islands. Recent data highlight why urgent, targeted action is needed. Water security is central to sustainable development in the Cook Islands, supporting public health, tourism, and livelihoods. Yet water supply systems vary widely across islands. Climate variability and extreme weather events are intensifying existing pressures. Prolonged dry spells reduce water availability, while heavy rainfall increases the risk of contamination, disrupting services and raising health concerns, particularly in communities with limited treatment and storage capacity. Uneven Access and Growing Risks Households across the Pa Enua, the outer islands excluding Rarotonga, face water vulnerability. Most rely on rainwater harvesting and household storage, with limited access to treated or piped water systems, leaving communities highly exposed during dry periods and times of increased demand. The 2021 census indicates that 85% of households are connected to public water mains and that more than half of households have a water tank. Still, approximately one-third of households depend on decentralized rainwater harvesting systems for their drinking water and one-in-five households had installed filtered systems to pipe drinking water into the house. Reliance on rainwater is particularly pronounced in the Pa Enua, where households increasingly turn to private solutions to secure reliable drinking water access. However, the high upfront and maintenance costs of these measures place them beyond the reach of many households, leaving many exposed to water shortages during droughts and disruptions following extreme rainfall. Infrastructure Constraints Infrastructure and asset management further limit system performance. On Rarotonga, projected water demand is expected to reach 11,200 cubic meters per day (m3/day) by 2031, with an additional 1,120 m3/day required to account for non-revenue water losses. required to account for non-revenue water losses. Leakage, aging assets, and limited monitoring reduce efficiency and heighten supply risks as demand grows. However, significant reforms approved in late 2025 and early 2026 are expected to strengthen the long-term financial sustainability of the water sector and promote more efficient use of scarce water resources. Central to these reforms is a new water tariff effective 1 October 2025, which introduced a uniform volumetric charge of NZ$1.40 per cubic meter (1,000 liters) consumed, plus value-added tax, for all customers, regardless of usage type. The government subsidizes up to 38,000 liters per month for eligible domestic connections and covers water charges up to the subsidized amount, while consumers pay for any usage above the allocation. Households without water meters are charged a fixed monthly fee until metering is installed. The rollout of domestic water meters is ongoing and is expected to be completed for existing customers by June 2027. By linking charges to actual consumption while providing targeted support for households, the reforms help establish a more sustainable funding base for future water infrastructure upgrades and encourage greater water conservation. National planning frameworks underscore the continued importance of rainwater harvesting across both Rarotonga and the Pa Enua. Even with reliance on rainwater, ensuring a safe and reliable supply under changing climate conditions may require greater attention to consistent standards for storage, maintenance, and water safety. Implications Persistent water insecurity has far-reaching implications. Service disruptions affect households, tourism operators, and public facilities, while contamination risks undermine health outcomes, especially where contaminated water is consumed. The need for private storage and treatment can also widen inequalities, placing a heavier burden on low-income and remote households. Strengthening water security is therefore not only an infrastructure challenge but a critical component of climate adaptation, public health protection, and economic resilience in the Cook Islands. Policy Priorities Targeted policy reforms and sustained investment are essential to reduce systemic risks. Recent progress, including the Te Mato Vai water supply program and strengthened monitoring under the National Sustainable Development Agenda, provides a solid foundation to build upon. Priority actions include structured programs to manage non-revenue water, improve asset management, and strengthen leakage control, particularly on Rarotonga. In the Pa Enua, establishing climate-resilient standards for harvesting rainwater, storage, and household systems will be critical to improving safety and reliability. The Cook Islands Building Code 2019 recognizes rainwater harvesting and water storage tanks as important components of water security, particularly in areas where households rely on rainfall as their water source. The Code provides detailed guidance on the design, sizing, installation, and maintenance of water tanks to ensure a reliable supply and protect water quality, including requirements for screened inlets and overflows, appropriate tank and roofing materials, and measures to prevent contamination. While the Code recognizes the importance of water storage infrastructure and sets standards for its construction and operation, water tanks are generally exempt from building permit requirements. Strengthening water safety planning, supported by improved monitoring, data collection, and community awareness, will help manage contamination risks following extreme weather events. Together, these measures can improve service reliability, protect health, and enhance resilience across the Cook Islands. Policy Recommendations Several policy actions are recommended to operationalize these priorities. First, accelerating investment in climate-resilient water infrastructure is essential to address service gaps and improve system performance. This includes rehabilitating aging reticulated networks to reduce leakage and nonrevenue water; expanding storage capacity to manage rainfall variability; and developing decentralized supply solutions, such as rainwater harvesting and small-scale systems for outer islands, where centralized infrastructure may not be viable. Prioritizing investments based on vulnerability, population needs, and economic importance, particularly in tourism-dependent areas, would improve efficiency and maximize the impact of development. Second, strengthening sector governance is critical to ensure effective service delivery and long-term sustainability. This involves clarifying institutional roles and responsibilities across central and island-level authorities; improving coordination among agencies responsible for infrastructure, health, and the environment; and promoting behaviors around safe water storage. Expanding on existing cost-recover mechanisms, the introduction of separate tariff structures for commercial customers would help ensure adequate funding for operations and maintenance while maintaining affordability. Third, adopting an integrated water resources management approach would support more sustainable use of limited freshwater resources. This requires improving data collection and monitoring systems to track water availability, abstraction, and demand across islands; strengthening protection of groundwater lenses and surface catchments from overuse and contamination; and integrating water planning with land-use management and tourism development policies to help mitigate competing demands and reduce risks to water security. In addition, incorporating climate risk assessments into planning processes would ensure that infrastructure investments are robust to future changes in rainfall patterns, drought frequency, and extreme weather events. Finally, capacity building and community engagement are essential to sustain improvements in the water sector over time. Strengthening the technical and managerial capacity of local service providers would improve system maintenance and operational efficiency, while public awareness campaigns can promote water conservation, reduce wastage, and encourage household-level solutions such as rainwater storage. Engaging communities in the planning and management of water systems would also enhance ownership and accountability, contributing to more reliable and resilient service delivery across the Cook Islands. Way Forward The proposed Water Security, Alternative Energy, and Vital Ecosystems Restoration Project intends to strengthen climate resilience, water security, and renewable energy access further. The project hopes to expand renewable energy investments, including solar PV, and improve water security in the southern Pa Enua. The project aims to support stormwater management, upgrades to renewable energy systems, and institutional capacity development. Note: The Author wishes to acknowledge the following for their invaluable contribution to the article; Leigh Chan, Neeta Pokhrel, Allison Woodruff, and Kristina Katich of ADB’s Water and Urban Development Sector Office, Sectors Department 2, ADB; and Lavinia Tama, ADB’s Principal Country Officer for the Cook Islands. Resources Asian Development Bank. Water Security, Alternative Energy, and Vital Ecosystems Restoration Project in the Cook Islands. Government of the Cook Islands. 2025. Cook Islands Climate Change Survey Report 2023–2024. Government of the Cook Islands. 2023. National Sustainable Development Agenda Indicator Report. Government of the Cook Islands. 2021. 2021 Census of Population and Dwellings. Rarotonga. Government of the Cook Islands. 2021. National Infrastructure Investment Plan. Government of the Cook Islands. 2019. Cook Islands Building Code 2019 Government of the Cook Islands. 2014. Te Mato Vai Water Supply Master Plan. Ask the Experts Isoa Wainiqolo Senior Economics Officer, Pacific Department, Asian Development Bank Isoa Wainiqolo works at ADB’s Pacific Subregional Office in Suva, Fiji. He currently serves as the country economist for the Cook Islands, Niue, and Tonga, supporting ADB’s programs and initiatives. Prior to joining ADB in 2019, he worked as an economist and senior economist at the Reserve Bank of Fiji for 12 years. He holds a master’s degree from Columbia University in the US and a bachelor’s degree in economics and accounting from the University of the South Pacific. Leave your question or comment in the section below: View the discussion thread.