Several empirical studies have analyzed the factors that influence local privatization. We examine the influence of transaction costs and political factors on local governments' choices through new variables. We consider two relevant services accounting for different amounts of transaction costs: water and solid waste delivery. Our results show that privatization is less common for water, which has higher transaction costs. Furthermore, we find that municipalities with a conservative ruling party privatize more often regardless of the ideological orientation of the constituency. Finally, we find that intermunicipal cooperation may be a suitable organizational form for some municipalities.