This study based on a household survey quantifies, for the first time, the impact of small water supply networks on household water access conditions in rural areas in Niger. Niger is a very poor Sahelian country suffering from climate change. We use the propensity-score matching method to analyse data from a survey carried out in 2017. In order to perform a rigorous impact analysis, we compare water access conditions in 10 randomly selected villages, two of which are beneficiaries of small water supply networks and eight of which are not. Thus, the sample includes 596 households. The results of the matching method are different from those obtained by a simple difference in means between the two groups. We lead robustness analysis to reduce the bias due to unobservable characteristics. We obtain similar and conclusive results with respect to the baseline specifications. This legitimises the value of the impact assessment method for providing unbiased estimates for policy makers. The article shows that the water supply networks have improved the water access conditions such as its cost (which must be accessible to all) and its availability, which are key vectors for achieving the Sustainable Development Goals. The lack of immediate availability of drinking water increases the distance to water sources and the time spent on collecting water, to the detriment of children’s school attendance, especially for girls, and women income-generating activities, as well as the time spent on educational activities. Clearly, this study shows that policies which target the implementation of small water supply networks in rural areas would generate a real impact in terms of poverty alleviation for rural households.