The non-market value of reclaimed wastewater for use in agriculture: a contingent valuation approach

The reuse of treated water for agricultural irrigation is considered a promising option in regions facing water scarcity problems and there is an increasing number of reuse projects going on in southern European countries. The aim of this paper is to estimate the non-market benefits that society attaches to the use of reclaimed wastewater for agricultural purposes, as part of the economic assessment needed to evaluate the viability of this water management option. For this purpose, a contingent valuation study has been developed in the Segura River Basin in south-eastern Spain, interviewing 352 individuals from a representative sample of the basin’s population. Results show that the use of reclaimed wastewater for irrigation has significant non-market environmental benefits (mean willingness to pay of €5.13 per month per household, which adds up to a total annual value of €23.3 million). In terms of volume, these benefits represent €0.31 m–3. Therefore, it can be concluded that the non-market benefits of using reclaimed wastewater for agriculture justify its implementation, as they overcome the average treatment costs of €0.16-0.26 m–3. Additionally, the analysis of preference heterogeneity suggests that the use of reclaimed wastewater in agriculture is more acceptable to people if they are made aware of their current payment for water sanitation. The inclusion of these non-market benefits in the overall assessment of water policy options will lead to better informed and more efficient water management decisions