Which water and sanitation systems deliver the greatest health benefit per dollar and remain reliable for decades?

Evidence(5)

1. 

   Effectiveness of stand-alone and multi-component water, sanitation and hygiene interventions to reduce mortality in childhood: a network meta-analysis | Nature Water

   [1]

   19 Sept 2025

   This component network meta-analysis compared stand-alone and combined WASH interventions for childhood mortality in low- and middle-income countries. It associates reductions with improved water quantity and drinking water. Hygiene and sanitation performed better after water supply improved. Packages showed no synergy and sometimes antagonistic interactions, especially with intensive behavior change.

   1

   For health per dollar, the result favors sequencing: improve water quantity and drinking-water conditions before adding sanitation or hygiene components. The study does not report intervention prices, maintenance costs, or multi-decade functionality. Use its health-effect ordering with local lifecycle costing and reliability evidence, rather than treating it as a complete investment ranking.

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2. 

   Comparative economic analysis of urban sanitation interventions in low- and middle-income countries: a systematic review | Journal of Water, Sanitation and Hygiene for Development | IWA Publishing

   [2]

   Date unavailable

   This systematic review assessed 36 economic analyses covering 22 methods, 44 cities, and 23 countries. It found heterogeneous urban sanitation costs and weak comparability across settings. No study fully defined a realistic least-cost without-project standard. Only one used incremental costs against that standard; most reported time horizons spanned 10–30 years.

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3. 

   Effectiveness of interventions to improve drinking water, sanitation, and handwashing with soap on risk of diarrhoeal disease in children in low-income and middle-income settings: a systematic review and meta-analysis - The Lancet

   [3]

   Date unavailable

   The frozen snapshot contains only navigation, advertising, and interface text for the Lancet article. It does not expose the abstract, methods, results, effect estimates, intervention costs, or follow-up evidence. Consequently, this snapshot cannot establish which drinking-water, sanitation, or handwashing intervention reduced diarrheal disease, by how much, or for how long.

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4. 

   Effects of a community-driven water, sanitation, and hygiene intervention on diarrhea, child growth, and local institutions: A cluster-randomized controlled trial in rural Democratic Republic of Congo | PLOS Medicine

   [4]

   Date unavailable

   This cluster-randomized trial evaluated a WASH program across 332 villages in 121 clusters in the Democratic Republic of Congo. After 3.6 years, diarrhea and child length-for-age did not improve. Use of improved water rose 24 percentage points, improved sanitation 18 points, and WASH institutions scored 0.40 points higher versus controls.

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5. 

   Water Supply, Sanitation, and Hygiene - Injury Prevention and Environmental Health - NCBI Bookshelf

   [5]

   Date unavailable

   This chapter synthesizes WASH coverage, health effects, delivery models, costs, efficiency, and sustainability. Meta-analyses reported diarrhea risk ratios of 0.66 for water, 0.72 for sanitation, and 0.60 for handwashing with soap. Lower-technology options generally showed higher returns, while cost-effectiveness widely varied with density, geology, service level, and local cost conditions.

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