Water Quality and Financial Analysis of a System Combining Rainwater and Greywater in a House

This study aimed to evaluate the installation of a system that combines rainwater to wash clothes and greywater to flush toilets in a house located in Florianópolis, southern Brazil. The evaluation consisted of determining the potable water savings, performing a financial analysis, and verifying the possibility of using rainwater and reusing greywater according to the local legislation. The reduction in potable water consumption was determined by comparing the monthly water and sewage bill, before and after installing the system, combining rainwater and greywater. The financial analysis was performed considering the financial benefits, operational costs, costs for installing the system, and local water tariffs. After installing the system, there was a decrease of 38.0% in the monthly potable water consumption, which represents a decrease of 7.00 m3 in the monthly potable water consumption. The payback periods for the old and new water tariffs were equivalent to, respectively, ten years and seven months, and eight years and five months. Both rainwater and greywater had parameters with concentrations higher than the limits established by the legislation. Therefore, the rainwater had to go through a device for discarding the first flush and needed disinfection; and the greywater needed to go through a treatment process. The results indicated that the system combining rainwater and greywater shows significant potential for potable water savings, which can be a good alternative to the preservation of potable water resources. It is important to note that current studies on rainwater use and greywater reuse are mainly related to non-potable purposes, but it was shown herein that rainwater can be used for washing clothes.

Wastewater Tariffs in Spain

Urban water cycle services culminate in wastewater services; that is, with the collection, transport, and treatment of wastewater. Wastewater management in Spain is not a straightforward issue. In fact, the European Commission has initiated infringement procedures against Spain for not fully complying with the Urban Waste Water Treatment Directive. Yet, appropriate collection and treatment would require a large monetary investment that is increasingly difficult to carve out of existing government revenues. In this context, wastewater pricing emerges as a significant tool for achieving cost recovery and environmental protection aims. In Spain, local governments are responsible for providing wastewater services in urban areas and for setting the prices for those services. Spanish regional governments are in charge of specific pollution taxes on wastewater, which are included in the individual users’ water bills. Moreover, in most Spanish cities, the urban water tariffs for wastewater services (like water supply tariffs) are different for different users, representing the most common distinction between residential and nonresidential users. Additionally, specific tariffs are frequently imposed for different customer groups within both categories. In this respect, it is common to include pollution charges for industrial users, increasing their water prices according to the environmental impact of their wastewater discharges. The result is a very complex map of water-pricing and taxing in Spain.

Irrigation water tariffs: lessons for Portugal

This article aims to provide a comprehensive review of the empirical literature on irrigation water tariffs in several countries, particularly in Mediterranean European countries, and to offer insights into the Portuguese status quo. We analyze a wide variety of tariffs, and the largest differences among them are discussed. In various countries, in those regions with a higher demand for water, irrigation water tariffs are more complex and higher, varying from country to country and, within the same country, from region to region. Large differences in irrigation water tariffs among different water-use associations were found, mostly because each one has its own objectives. A SWOT analysis was performed for Portuguese irrigation water tariffs. It concludes that there is much to do to enact the proposed strategies, including recovering operation and maintenance costs and promoting the efficient use of water and efficient water allocation. Furthermore, the farmers' position in the value chain must be improved along with their ease of access to credit, thus increasing the added value of the produced goods.

Water Tariffs in Spain

In the current context of climate change, water scarcity has become the center of an intense debate in recent years. Spain is a country affected by strong regional differences in terms of weather; thus, the quality and availability of water resources vary widely depending on the area, and the country is plagued by droughts and problems with water quality. Nevertheless, urban water prices in Spain are among the lowest in the European Union. Moreover, it is a federal country where subcentral governments (regional and local) are autonomous entities with different responsibilities in the design of water policies. The extremely atomized local panorama and the strong power of the regional governments have led to a highly complex system with a wide range of water price levels and structures. Since the heterogeneity is so great, this article focuses on the tariffs related to the water supply service in the 15 largest Spanish cities. In general, urban water tariffs commonly distinguish between residential and non-residential users. Additionally, there are usually specific tariffs for different customer categories within both residential and non-residential users, which are not always justified in terms of the equity principle. It is important to note that in most cities the eligibility criteria for these special tariffs usually add more complexity to the tariff system and adversely affect horizontal equity. All these factors contribute to the great complexity of Spain’s water-pricing map. The heterogeneous tariff system found in most Spanish cities runs counter to equity principles and can send the wrong signal to users about water scarcity, thereby hindering compliance with the resource sustainability objective. Thus, most Spanish cities require a simplification of the tariff system.

An Assessment of the Widespread Use of Increasing Block Tariffs in the Municipal Water Supply Sector

The design of municipal water tariffs requires balancing multiple criteria such as financial self-sufficiency for the service provider, equity among customers, and economic efficiency for society. Globally, various forms of water tariffs are in use (e.g., tariffs based on fixed or volumetric charges, single and two-part tariffs, and increasing or decreasing block tariffs) but increasing block tariffs (IBTs) have become popular worldwide over the last few decades for two main reasons. Apart from the fact that IBTs incentivize households to save water by charging large volumes at a higher price, there is a widespread belief that IBTs are pro-poor. The latter would be the consequence of providing all households with a minimum amount of water at a low (subsidized) price while large water users pay higher prices. However cross-subsidization between wealthy and poor households will occur only if poor households’ consumption falls in the low (subsidized) block and if rich households consume in the higher block and pay a price that is above the average cost of supply. These two conditions are rarely met in reality and IBTs often fail to allocate subsidies to the poor effectively. There are a few examples of water utilities making adjustments to the tariff to take into account that poor households with large families are likely to be adversely affected by IBTs. However, the provision of a minimum amount of water for free (as in South Africa), the design of household-specific low-cost water allowances (as in California), or tariffs being adjusted based on household size do not usually improve the targeting of subsidies to the poorest households. The widespread use of IBTs is difficult to rationalize, in particular while knowing that the use of a (simple) uniform volumetric tariff where water provision is charged at its full cost could improve social welfare by removing price distortions and would be easier for households to understand than IBTs. This simple tariff could be combined with some consumer assistance programs to help the poorest households pay their bills.

Factores explicativos de la demanda municipal de agua y efectos en el bienestar de la política tarifaria. Una aplicación a la cuenca del Segura

In this article urban water demand is analyzed using data of 42 municipalities located in the Segura River Basin for the period 2000-2006. The econometric approach shows that price, income and population are the most important variables for explaining urban water demand changes. Water tariffs achieve moderate savings due to the price inelastic behavior of demand (-0,4). This is typical of necessary goods without substitutes. Calculus made shows that the increment in tariffs, necessary to reduce 10% consumption, means a consumer surplus reduction between 8 and 9,5 euros per person (and year). There is also a minimum of water consumption in homes, 84 litres per capita per day that cannot be affected by tariffs. Income and population increments have deeper impact than price for explaining changes in urban water demand. Predictions about these variables are major for a proper hydraulic management.