Territorial Inequalities and Convergence in Water Policy: The Spanish Case

Numerous investigations have shown that water quality affects social justice. Therefore, the quality of water should be the same in all territories of a country. Statistically significant differences in Spain have been verified regarding some variables that determine water quality. Regional differences of these variables could be regarded as a source of divergence in population health.

In this paper we analyze the evolution of the observed regional differences. Seven variables related to water quality have been studied: treated wastewater, treated wastewater disposal, reclaimed wastewater, water supplies, household water supplies, water supplies for other uses, and the percentage of water lost in distribution. The Spanish National Institute of Statistics is the data source and the time period covered is 1999-2006. Besides the descriptive analysis of the variables, we apply the concepts of beta and sigma convergence, which both derive from the economic literature related to economic growth.

The results show that all variables demonstrate beta-convergence. However, the methodological change that occurred in 2004 made it impossible for the reduction in the dispersion over time for all variables to be verified. In particular we observed very weak convergence in the volume of treated wastewater and reclaimed water. Stronger convergence appears in the volume of water supply, especially in the case of supply for other uses.

Despite the convergence, there are also substantial differences among regions. Consequently, further development is needed in consolidating the process of reducing regional disparities in water quality as a complementary way of reducing inequalities in health.