Valuing Treated Wastewater and Reuse: Preliminary Implications From a Meta-Analysis

Over the past few years, several empirical studies have estimated the economic benefits of treating and reusing wastewater for different purposes and in different countries. This work has resulted in an expanded data pool potentially usable for evaluating the social and economic implications of wastewater investments, particularly those incorporating reuse projects. We present the results of a systematic and comprehensive review of available empirical studies that assessed individual willingness-to-pay (WTP) estimates of recycled wastewater. Using a meta-analysis method (MA), we investigated the results of 84 WTP estimates from 22 international studies covering 12 countries. From our general meta-regression model, we estimated the mean WTP for recycled wastewater at US$ 52.62 per-household/per-year. We find that WTP can vary in a systematic and predictable way with respect to key factors that determine an individual’s WTP for recycled water, such as socio-economic and contextual characteristics as well as the individuals’ attitudes and perceptions concerning recycled water. We demonstrate that such categories of variables are important for the potential use of MA for value transfer. This finding can be useful to inform and guide research and development on future empirical valuation studies, and to facilitate the use of value-transfer methods through the MA model.