Wastewater reuse is an activity that reduces pollution from discharges while increasing the available water resources. However, the high financial costs of this activity affect the viability of projects, either because of low water productivity or because of the presence of a cheaper alternative, such as natural water sources. The existence of environmental or social benefits makes reuse a positive option for society for its environmental and social benefits. This leaves the public sector to decide whether the benefit obtained justifies its participation in the development of reuse programs, for which it is necessary to use a tool such as cost-benefit analysis, which combines diverse costs and benefits. This article studies the potential for water reuse in Spain and the importance of informed decision-making, based on information regarding water stress, wastewater reuse, and the case study of the Canal de Isabel II (Madrid). The results confirm the potential of wastewater reuse; agriculture has a water productivity below EUR 1 per cubic meter and industry and services need their own sources of water, but financial constraints prevent the greater use of reclaimed water in all economic sectors and public intervention is necessary to obtain the optimum scenario for society. The case study from Madrid that we have analyzed in this paper shows the importance of considering all factors, since the results of prioritizing the financial criterion would have been detrimental to society, in the form of EUR 200 million in environmental damage, while EUR 740 million of non-financial benefits would make wastewater reuse an advantageous alternative for society, thus justifying the public investment.

The limited availability of water at low prices and the current scheme for specific supply arrangements (SSA/REA), both determined at the political level, explain that the goal of being self-sufficient in terms of forage consumption is currently unattainable in the Canaries. The “PFORCA” Plan aims to counteract this reality and increase their level of self-sufficiency. The financial aid relating to the REA reduces the amount payable for the imported fodder (annual 83,000 t) versus local product, which influences the decision making by farmers. According to calculations, performed by reusing the water instead of discharging, Maralfalfa production could be competitive against imports, being financially viable with water prices in a range of 0.20–0.30 €/m³ (prices perfectly acceptable for reclaimed water with low levels of treatment, but fulfilling requirements reuse of Spanish law, RD 1620/2007). The economic contribution of forage crops could represent the creation of 640 new jobs, the enhancement of land currently abandoned, plus an increase in Gross Domestic Product (GDP) of the archipelago on more than 23 million € (M€), product of the substitution of imports by local production. Also, it would help to save the REA’s aid (6 M€).

This paper empirically analyses the effects of the tax complexity and other elements, such as natural resource revenues, public expenditure, and the capacity of the statistical system, on the efficiency of Ecuadorian Customs Administration. For this purpose, the methodology used consists of modeling a stochastic production frontier whose estimation procedure is based on the maximum likelihood method for a data panel composed of six countries: Bolivia, Chile, Colombia, Ecuador, Peru, and Panama for the period from 2006 to 2017. The results of the study show that the countries whose tax system has a lower degree of complexity present a better level of revenue collected and tax effort as well as an improvement in the quality and dissemination of national statistical data. Furthermore, this paper provides evidence that the tax effort tends to decrease when the price of crude oil is on the rise.

El presente trabajo tiene dos objetivos principales. Por una parte, analizar los costes de producción del agua regenerada y los servicios asociados para su reutilización en la producción de bienes y servicios. Y, por otro lado, determinar el valor económico de las actividades productivas sustentadas con estos recursos no naturales. Se ha podido analizar actuaciones y proyectos que representan más del veinte por ciento del volumen total de agua reutilizada en España, obteniendo una estimación de indicadores de costes de inversión y de explotación, junto a un indicador de coste medio de producción y distribución de 1,10 €/m3. A partir de indicadores de productividad se estima que el valor económico de los bienes y servicios producidos por la reutilización es de unos 2.165 millones de euros anuales.