This paper describes an economic cost-benefit analysis of the Koror-Airai drinking water safety plan from Palau to demonstrate the value to society of the drinking water safety planning approach in the long term. The cost-benefit analysis for implementing the Koror-Airai drinking water safety plan showed that a return of US$ 6.00 was expected on every US$ 1.00 invested towards implementing the plan. The case study provides an effective advocacy tool for the promotion of drinking water safety planning both in the Pacific region and globally.