Economic efficiency of sanitation interventions in Southeast Asia Guy Hutton, U-Primo Rodriguez, Asep Winara, Nguyen Viet Anh, Kov Phyrum, Liang Chuan, Isabel Blackett and Almud Weitz ABSTRACT Economic evidence on sanitation supports decisions on resource allocation and selection of efficient and affordable sanitation interventions. This study presents the economic efficiency (costs versus benefits) of sanitation interventions to better manage human excreta, from 47 field sites, covering six countries of Southeast Asia (Cambodia, China, Indonesia, Lao PDR, the Philippines and Vietnam). Costs were estimated in each location, while benefits (improved health, avoided water pollution, reduced sanitation access time, resource recovery) were estimated using evidence from published studies and field sites. The economic return per currency unit invested, known as the benefit-cost ratio (BCR), and the cost per disability-adjusted life-year (DALY) averted were estimated. Across 25 rural field sites, pit latrines had a BCR of at least 5 in all countries, except Cambodia where the BCR was 2. In 22 urban field sites, septic tanks with wastewater management had a BCR of at least 2. Costs per DALY averted were found to be ‘cost-effective’ for most sanitation interventions in all countries. Economic performance declined significantly when considering non-use of facilities by households or unused infrastructural capacity. However, the economic net returns were positive under all pessimistic scenarios examined in one-way sensitivity analysis. This study demonstrates that sanitation is a highly profitable social and economic investment in six Asian countries. Guy Hutton (corresponding author) Water and Sanitation Program, World Bank, 55 Lodi Estate, New Delhi, 110003, India E-mail: ghutton@worldbank.org Kov Phyrum Water and Sanitation Program, World Bank, 113 Norodom Blvd, Phnom Penh, Cambodia Isabel Blackett Water and Sanitation Program, World Bank, Indonesia Stock Exchange Building, Tower 1, 9th Floor. Jl. Jenderal Sudirman Kav 52-53, Jakarta 12190, Indonesia Almud Weitz Water and Sanitation Program, World Bank Group Singapore Office, 10 Marina Boulevard, Marina Bay Financial Center, Tower 2, #34-02 Singapore 018983 U-Primo Rodriguez Economics Department, University of the Philippines, Guerrero corner Osmeña Sts. Diliman, Quezon City, 1101, Philippines Asep Winara Mitra Lingkungan Duta Consult (MLD), Ventura Building, 4th floor, Suite 405, Jl. R.A. Kartini No. 26, Cilandak, Jakarta 12430, Indonesia Nguyen Viet Anh Institute of Environmental Science and Engineering (IESE), Hanoi University of Civil Engineering, 55 Giai phong Road, Hai Ba Trung District, Hanoi, Vietnam Liang Chuan Yunnan Academy of Social Sciences (YASS), 577 Huan Cheng Xi Lu, Kunming City, Yunnan Province, 650034 China Key words | Asia, benefit-cost ratio, capital cost, economic return, recurrent cost, sanitation Additional geographic key words | Cambodia, China, East Asia, Indonesia, Lao PDR, Philippines, Southeast Asia, Vietnam This paper is in the public domain: verbatim copying and redistribution of this paper are permitted in all media for any purpose, provided this notice is preserved along with the paper’s original DOI. Anyone using the paper is requested to properly cite and acknowledge the source as Journal of Water, Sanitation and Hygiene for Development 4(1), 23–36. 23 Journal of Water, Sanitation and Hygiene for Development | 04.1 | 2014 doi: 10.2166/washdev.2013.158