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.

Concerns about enduring low rural sanitation coverage figures in Cambodia prompted a series of studies providing insight into overall sector performance, sanitation demand and existing supply chains. Findings from the research led to the formulation of a sanitation marketing pilot aiming to make affordable, desirable latrines available through market channels. Option design, contractor training, awareness raising and marketing are the main components of the programme, implemented in two provinces. To date (22 months since inception) the project has resulted in a branded, low-cost pour-flush latrine sold by trained suppliers, who have sold more than 7,400 units. Planned next steps include expanding technology choices (still lower costs, and/or suitable for challenging physical circumstances), developing stronger linkages with micro-credit schemes and developing approaches for scaling up the approach.