I apply a duration model to the study of factors determining privatization of local water services. I assess how the influence of these factors changes as time goes by. I use a sample of municipalities from the Spanish region of Catalonia during the six terms of office taken place during the 1980-2002 time range. I hypothesize a dynamic neighboring effect, which is not rejected by the data: in a first phase (early eighties), water privatization is more likely in regions where there is no previous privatization; in a second phase (nineties), the opposite happens. The way other factors influence the privatization decision also evolve during the two decades under study, from a priority to fix old infrastructures to a concern about service efficiency. Budgetary shortfalls seem to encourage privatization only in times of huge economic struggle. The political sign of the government may influence the mode-of-production decision if there is no consensus about the most efficient one.

Key words: privatization, water utilities, duration model.
JEL codes: C41, H11, H42.