Low-cost domestic rainwater harvesting in rural southeast Madagascar: A process and outcome evaluation

In settings where communities rely on unimproved water sources, household rainwater harvesting (HRWH) may improve the quality and quantity of water available. This research presents results from a two-year controlled before-and-after study that evaluated the impact of low-cost HRWH on household water collection habits, hygiene practices and prevalence of childhood diarrhoea in rural Madagascar. The study assessed system functionality, water quality and the acceptability of requesting household financial investment (16–20 USD). Surveys were administered to enrolled intervention households (n = 138) and control households (n = 276) at baseline and endline. Water quality tests at endline compared microbial contamination in a sub-sample of HRWH systems (n = 22) and public water sources (n = 8). Difference-in-difference analyses were used to compare changes in outcomes between study arms at baseline and endline. At endline 111 (75%) of systems were functional with an average age of 1.25 years. Microbial contamination was 39.3 TTC/100ml in community water sources compared with 23.3 TTC/100ml in the HRWH systems (coef: -16.0, 95CI: -37.3 to 5.2, p = 0.133). 85 (57%) of households completed their repayment plans while remaining households owed on average 3.7 USD. There was weak evidence to suggest that intervention households collected more water per capita day than controls (adj coefficient: 3.45; 95CI: -2.51 to 9.41, p = 0.257). Intervention households had 11% higher absolute risk of owning a handwashing station compared against controls (95CI: 0.00 to 0.23; p = 0.06). There was no evidence of differences in ownership of soap or prevalence of childhood diarrhoea between study arms. Overall, operation and maintenance of the systems remained high, users demonstrated willingness to pay, and there was weak evidence that water provision at the household increased domestic consumption. However, the systems did not provide contaminant-free water. We conclude that HRWH using low-cost, locally available materials can increase household access to water in areas reliant on limited communal water sources.