Resident interview questions.

Very small islands in Indonesia face challenges in accessing clean water due to limited space for building water resource facilities, such as reservoirs. Most of the time, the inhabitants of these islands rely on rainwater and wells, which are not sustainable sources due to drought seasons and seawater intrusion. To address this issue, Seawater Reverse Osmosis (SWRO) can be implemented in these areas where seawater is abundant. However, there may be obstacles when applying SWRO systems in such environments. This study aimed to assess the capabilities of SWRO facilities, and the obstacles involved in evaluating clean water access on very small islands. We used a combination of structured questionnaires, interviews, and direct observations on two small islands in Indonesia, Belakang Padang Island and Labu Island. On Belakang Padang Island, we interviewed the water resource manager in October 2022 and March 2023 and surveyed 61 households in the Tanjung Sari subdistrict in October 2022. On Labu Island, we interviewed the staff of the SWRO system and surveyed 35 coastal households in September 2023. On both islands, the government improved residents’ access to clean water by constructing SWRO facilities in 2016 on Belakang Padang Island and in 2021 on Labu Island. However, on Belakang Padang Island, the system was not operational when we visited on March 15, 2023. The main obstacles were slow bureaucratic processes for repairs and maintaining the operation of SWRO facilities. These problems need to be addressed before expanding the implementation of this system to other very small islands in Indonesia.