Securing Samoa’s Water Future: A 10-Year Masterplan for Sustainable Supply

Samoa Water Authority supplies nearly 90% of Samoa’s population with piped water. Sourced from both surface and groundwater, water is treated through sand filtration and chlorination before distribution to the main islands of Upolu and Savai’i, as well as smaller islands like Manono.

But growing demand, combined with climate change and environmental stressors, has made supply less reliable. Boreholes are increasingly affected by salinity due to shallow drilling and over-extraction, while more frequent and intense storms are causing erosion, which increases sedimentation and turbidity in rivers. Prolonged dry spells and previously rare droughts are also impacting surface water sources, underscoring the need to develop sustainable and climate-resilient water systems.

Samoa’s last national water masterplan was developed in 2011. Much has changed since then, including a 13% increase in the country’s population, many of whom now choose to live in urban areas because of better access to key services. The new masterplan covers 2025 to 2035, offering a clear and practical roadmap to address emerging risks and strengthen supply reliability.

Integrating climate resilience into water systems
Increasingly frequent and intense storms, longer dry periods, and rising groundwater salinity are impacting Samoa’s water supply and the authority’s ability to treat and distribute it effectively. The masterplan emphasizes climate and disaster resilience for Samoa Water Authority’s network of boreholes, water treatment plants, and distribution pipelines, including innovative projects that address erosion and sedimentation concerns.

For example, the Ministry of Natural Resources and Environment has successfully piloted the use of “biolog” filters (natural barriers made from coconut fibers) placed along riverbanks to prevent storm runoff into crucial water sources. The masterplan proposes installing biolog filters along eight river locations to protect water quality and reliability.

The challenges of supplying water across Samoa reflect the importance of responding effectively to the Pacific region’s changing needs, especially in terms of mitigation and adaptation.

Investing in infrastructure and supply security
Investment in infrastructure is a key priority for social and economic development. To serve Samoa’s growing population, especially in rapidly expanding urban areas, the masterplan identifies short-, medium- and long-term infrastructure investments.

To secure supply in areas affected by groundwater salinity, recommended investments include larger drilling rigs and geo-resistivity tools to identify deeper, higher-quality aquifers. In rural Upolu and Savai’i, efforts will focus on improving equity of access, such as combining neighboring systems and connecting new villages to the national drinking water supply.

In Samoa’s capital, Apia, and its growing urban fringes, existing infrastructure will be upgraded to improve reliability. For example, a large 5,000 cubic meter water tank that currently operates at two-thirds capacity due to leaks will be rehabilitated or relocated. Additional improvements will support supply in anticipation of a new multipurpose dam.

Digitizing water operations
The masterplan also outlines how digital technologies can be integrated across Samoa Water Authority’s operations. Proposed upgrades to customer information and billing management systems aim to improve accuracy and efficiency alongside advanced network monitoring and supervisory control and data acquisition (SCADA) tools that enable faster detection of leaks and rapid response to emergencies.

The upgrades are expected to improve customer service, support more efficient maintenance and operations, and reduce nonrevenue water—often caused by aging infrastructure and poor leak detection. Some technologies are already being piloted, including drive-by radio-read meters and new SCADA tools to monitor pressure and chlorine levels.

Building technical and institutional capacity
Strengthening the knowledge and skills of Samoa Water Authority staff will be central to implementing the technological and infrastructure investments. The masterplan takes a long-term approach to building in-country capacity, ensuring access to specialized technical expertise over the next decade. ADB is working closely with Samoa Water Authority to support capacity development and supplement expertise through technical assistance.

The Water Supply and Investment Masterplan 2025–2035 provides a structured approach to securing Samoa’s water systems, phasing infrastructure upgrades, integrating digital monitoring, and building institutional capacity to ensure reliable and sustainable supply over for the next decade.

With support from the development community, Samoa has taken impactful steps to secure its water future and ensure that safe and sustainable water remains available to all, even in the face of climate change.

Samoa Water Authority. 2026. Samoa Water Authority Master Plan. Video. 25 January.

Samoa Water Authority. 2025. Samoa Water Supply and Investment Masterplan 2025–2035.