Résumé : A recent democratic experience in Tunisia in which a religious political party, Ennahdha, took over government for 3 years, provides an opportunity to learn from the interactions between the support to religious parties and improvements in infrastructure access rates. The correlation is not simple. Ennahdha did get, initially, political credit for improvements in regions with low initial networked water connections and it did deliver to the regions where they enjoyed political support. But the support faded as access improved, reducing the political attractiveness of the sector or at least reducing it importance as compared to other concerns voters may have. For sanitation, a correlation is also noted but it is much less robust. Tunisia’s experience suggests that the reputation of religious parties to care for the unmet needs of population is, at least, partially justified. However, water seems to be a much more effective and reliable voters’ grabber than sanitation and this may penalize investment in sanitation, a matter of concern since it has significant health and environmental effects. Moreover, once voters enjoy enough access and once they have seen the overall performance of the party, they treat the party like any other