Water and Sanitation Services for Megacities in the Developing World

A Working Paper

Water Science and Technology Board

Commission on Geosciences, Environment, and Resources



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Water and Sanitation Services for Megacities in the Developing World A Working Paper Water Science and Technology Board Commission on Geosciences, Environment, and Resources

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This page in the original is blank.

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PANEL ON SUSTAINABLE WATER AND SANITATION SERVICES FOR MEGACITIES Members John J. Boland, The Johns Hopkins University, Chair Arthur E. Bruestle, The World Bank Richard S. Engelbrecht, University of Illinois Steven A. Esrey, United Nations’ International Children’s Emergency Fund Donald T. Lauria, University of North Carolina Walter R. Lynn, Cornell University Rebecca T. Parkin, American Public Health Association Peter P. Rogers, Harvard University National Research Council Staff Gary D. Krauss, Study Director Ellen A. de Guzman, Project Assistant

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WATER SCIENCE AND TECHNOLOGY BOARD David L. Freyberg, Chair, Stanford University, Stanford, California Bruce E. Rittmann, Vice Chair, Northwestern University, Evanston, Illinois Linda M. Abriola, University of Michigan, Ann Arbor Patrick L. Brezonik, Water Resources Research Center, St. Paul, Minnesota John Briscoe, The World Bank, Washington, D.C. William M. Eichbaum, The World Wildlife Fund, Washington, D.C. Wilford R. Gardner, University of California, Berkeley Thomas M. Hellman, Bristol-Myers Squibb Company, New York, New York Carol A. Johnston, University of Minnesota, Duluth William M. Lewis, Jr., University of Colorado, Boulder John W. Morris, J.W. Morris Ltd., Arlington, Virginia Carolyn H. Olsen, Brown and Caldwell, Pleasant Hill, California Charles R. O’Melia, The Johns Hopkins University, Baltimore, Maryland Rebecca T. Parkin, American Public Health Association, Washington, D.C. Ignacio Rodriguez-Iturbe, Texas A&M University, College Station Frank W. Schwartz, Ohio State University, Columbus Henry J. Vaux, Jr., University of California, Riverside Staff Stephen D. Parker, Director Sheila D. David, Senior Staff Officer Chris Elfring, Senior Staff Officer Gary D. Krauss, Staff Officer Jacqueline A. MacDonald, Senior Staff Officer Jeanne Aquilino, Administrative Associate Etan Gumerman, Research Associate Angela F. Brubaker, Senior Project Assistant Ellen A. de Guzman, Project Assistant Anita A. Hall, Administrative Assistant Mary Beth Morris, Senior Project Assistant

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EXECUTIVE SUMMARY Water and sanitation services in the megacities of developing countries are inadequate for a large and rapidly growing number of urban residents. A history of nationally subsidized water services and lack of attention to cost recovery have limited the capacity of water and wastewater service providers to expand the network, treat water and wastewater, and fund repairs. In low-income communities, especially the squatter settlements that characterize many megacities, facilities for proper disposal of human wastes are seldom available; hygiene practices are generally poor; and water for household use is often inconvenient, insufficient, and contaminated. In many of the large cities, municipal and industrial wastewaters are rarely treated prior to disposal, and urban streams, rivers, and estuaries are severely polluted with human pathogens and toxic wastes. Diarrheal and respiratory infections that result from these conditions continue to be among the most frequent causes of sickness and death for infants and children. To help improve the prospects for sustainable water and sanitation services for megacities in developing countries, a U.S. National Research Council panel focused on five areas that should receive the attention of national governments; external aid agencies; technical consultants; scientists; technicians; providers of water, wastewater, and other sanitation services; health services; and the leaders of the affected communities. (As used here, the term “sustainable” simply means that the services are capable of being continued over time without deterioration.) The result was a set of five approaches for achieving improved megacity water and sanitation services. Improved Sanitation. Water and sanitation professionals must take a broader view of sanitation to prevent disease resulting from a wide range of activities and multiple exposure routes. The provision of a potable water supply and wastewater removal are necessary but not sufficient conditions for improving public health. Water supply and wastewater management should be well integrated with other community, environmental, health, and nutritional programs to create a more robust and effective approach to healthcare and disease prevention. As opposed to the setting of standards by particular programs, activities, or media, an integrated approach should focus on end

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results by considering and giving equal attention to all strategies and means for achieving those results in a cost-effective manner. Successful integration implies the avoidance of institutional barriers to the implementation of nontraditional approaches. Participatory Planning. Public water and wastewater service providers, health institutions, municipal and federal governments, and external aid agencies need to work together to place a higher priority on providing incremental water and sanitation improvements to the unserved residents of urban communities. This can be accomplished through participatory planning with the community, public education, and an openness to innovative technical approaches. These strategies should be compatible with the aspirations of the communities involved, their ability to maintain and upgrade the system, and the services people want and for which they are willing to pay. Financing. All people, including the very poor, are willing to pay a reasonable fee for convenient and reliable access to safe drinking water and the safe elimination of household waste. It follows that providers of drinking water and wastewater services should strive to become financially sound and self-sufficient entities that can collect revenues from customers sufficient to maintain and expand system services as needed. The Role of Technology. Technical innovation should be based on carefully considered performance criteria appropriate to maintaining a healthy environment. The private sector can be an important contributor to the development of locally new technology and the provision of services. However, the participation of the private sector in service delivery and technology innovation requires the right market incentives, sound government policy, and appropriate and enforceable laws and regulations. Water Conservation and Reuse. By their very nature, megacities have larger impacts on water resources and suffer greater constraints on obtaining water than smaller urban or rural settlements. Effective management of water resources requires a holistic approach that considers water quantity, quality, and use within an entire watershed or catchment area. Conservation of water resources should be a priority for all megacities, and the value of water should be reflected in the design of tariffs and the metering of users. With appropriate treatment, reclamation and reuse of municipal wastewater for nonpotable uses can become an increasingly cost-effective conservation measure.

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INTRODUCTION This paper examines the challenge of improving water and sanitation services in the megacities of the developing world. Following a review of the current situation, it presents approaches to improved services in five areas: improved sanitation, participatory planning, financing, the role of technology, and water conservation and reuse. REVIEW OF THE CURRENT SITUATION After the United Nations declared the 1980s the Drinking Water Supply and Sanitation Decade, concerted efforts were made by both governments and external support agencies to improve the delivery of drinking water and sanitation services in developing countries (United Nations Development Programme, 1994). Yet while the coverage of urban drinking water services has improved over the last decade, the number of urban residents without adequate means to dispose of their household wastes has continued to grow (World Bank, 1992) (see Figure 1 ). In providing for wastewater removal, governments have generally focused on constructing sewers in city centers. Wastewater services rarely reach the poor residents living on the urban periphery or in informal settlements, where open drains and ditches commonly collect household waste. In most developing-country megacities, wastewater is rarely treated prior to disposal, and urban streams and rivers have become little more than sewage canals, carrying almost undiluted human and animal excreta, refuse, and industrial waste. Where drinking water service is presumed to be adequate and safe, the distribution systems are often poorly maintained and may suffer from leaks and intermittent system pressure. Negative pressure inside the pipe allows contaminated water from the surrounding soil to infiltrate the distribution system. Tests of household tap water in Mexico City, for example, showed significant variation in the percentage of samples that met the standard for microbiological safety (as measured by the chlorine residual), ranging from full compliance to as low as 16 percent among the political jurisdictions of the metropolitan area (National Research Council, 1995).

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FIGURE 1 Access to water and sanitation service in urban areas of developing countries, 1980 and 1990. Sanitation service in this figure indicates public sewers. Source: Adapted from World Bank (1992) from World Health Organization data.

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Foreign aid and other investments have traditionally focused on the development of drinking water supplies to the exclusion of wastewater systems and other aspects of sanitation. Relative to the amount spent on water services, sanitation has received only 15 percent of the total lending in the water and sanitation sector of the World Bank over the past 30 years (Bartone, 1994). This emphasis has reflected, in part, the priorities of borrower governments. From an economic perspective, investment in water supply encourages industrial and commercial development and has contributed to the growth of megacities. These large cities are often the engines that drive the development process for countries in the early stages of modernization. The demand for a convenient and adequate water supply for the urban family is often seen as a higher priority than wastewater removal, especially for poor urban residents. However, part of the reason for the perceived lack of demand for wastewater services is that very few options have been available or presented to unserved communities. The health consequences of inadequate drinking water and wastewater services fall most heavily on the poor. Urban populations in developing countries are growing most rapidly in the low-income, high-density districts, including the informal settlements (also termed squatter areas, favelas, shantytowns, and villas misérias) that can be found in most developing-country megacities. In these areas, there are few or no facilities for proper disposal of human wastes; water for household use is rarely convenient or sufficient and is often contaminated; hygiene is poor; and in the event of illness, access to medical treatment is difficult. Diarrheal diseases from gastro-intestinal and parasitic infections and acute respiratory illnesses resulting from these conditions are among the leading causes of sickness and death among infants and young children in the developing world (World Bank, 1993). It is estimated that in the developing countries, 3.2 million children under the age of 5 die each year from diarrheal diseases (World Health Organization, 1992). The disparity between those with and without access to clean water and a clean environment is strikingly evident within most large urban areas. Mortality rates are between 2 and 10 times higher for children living in the squatter areas of a city than for children living in areas with adequate drinking water, wastewater, and medical services and better nutrition and hygiene practices (Stephens, 1995). Even with deteriorating services, the more well-to-do can afford to either boil water or subscribe to services that guarantee convenient and good-quality water. The problem of lack of coverage for water and wastewater services has been the subject of numerous international forums and reviews. A declaration and plan of action to improve health, including safe water, wastewater removal, and other aspects of sanitation, was adopted in 1990 at the United Nations World Summit for Children and had been joined by 174 countries as of July 1995. The growing threat to public health and the environment from the scarcity and misuse of fresh water was recognized by 100 countries and 80 international, intergovernmental, and nongovernmental organizations at the International Conference on Water and the Environment in Dublin, Ireland, in 1992. In March 1994, representatives of governments met at the Ministerial Conference on Drinking Water and Environmental Sanitation in The Netherlands to assess the Drinking Water and Sanitation Decade of the 1980s and to develop an action program to implement the United Nations

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Conference on Environment and Development Agenda 21. The resulting statements stressed the need for integrated water resources management and a recognition that safe water in sufficient quantities and proper sanitation need to be provided to all people. Other resolutions from the Ministerial Conference focused on the need for emphasizing waste reduction and pollution prevention, enabling local partnerships to deliver local services in accordance with expressed needs and a willingness to pay, and giving priority to populations at greatest risk. Many of the themes of these international forums are reflected and reinforced in the approaches presented in the next section of this paper. 1 Historically, high subsidies in many countries have allowed large numbers of people to have access to drinking water and wastewater services at artificially low cost. While subsidies for these services are often promoted as antipoverty measures, the beneficiaries tend to be the wealthier residents of the city. Residents in low-income areas generally do not have in-home or on-property access to drinking water and must make do with high-cost and/or labor-intensive substitutes, such as carrying water long distances or paying high prices to water vendors. It is well documented that the urban poor not only pay a high proportion of their income for water (often 20 percent or more), but often pay more per month. In some cases, drinking water from vendors costs 25 to 50 times more per unit of water than the cost to households connected to the subsidized municipal system (World Bank, 1993). As a result, there is often insufficient clean water for the basic necessities of personal hygiene, household cleaning, and food preparation. With the false security of subsidies, government agencies that manage water and wastewater services have had little incentive to build institutional capacity or a sense of responsibility to the consumer. Water use is rarely metered, and billing systems are dysfunctional. Given the general scarcity of all public revenues and the escalating problems of large cities, water subsidies are shrinking in many places. Without the necessary operating funds, water and wastewater service providers lack the capacity to perform needed repairs or expand systems to serve new users. Service deteriorates, customers lose confidence, and revenues decline. In such circumstances, service providers have difficulty obtaining new loans or investments. The short- and long-term consequences of inadequate water and wastewater services are costly to society as a whole. Infectious and parasitic diseases linked to poor sanitation are the third leading cause of poor worker productivity in the developing world (World Bank, 1993). Without a piped water supply, one or more members of each household may spend otherwise productive hours each day carrying water from a standpipe, tubewell, spring, or stream. 1   It should be noted that there has been no attempt to be comprehensive in the topics presented in this paper. See United Nations Development Programme (1994) for a summary of the major international meetings on water resources, water supply, and sanitation.

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By their very nature, megacities have larger impacts on water resources than do smaller urban or rural settlements. Large quantities of surface water may be diverted, denying water supplies to downstream users. As a result of inadequate wastewater management, surface waters can become severely polluted, compromising the quality and availability of future supplies and creating future health risks. While ambient water quality improved in industrialized countries during the 1980s, it did not improve in middle-income countries, and it declined sharply in lower-income countries (World Bank, 1992). Large-scale development can impair important ground water recharge areas. Ground water is often extracted in excess of the aquifer’s natural recharge rate, and the results may include falling water tables, land subsidence, increased pumping costs, degraded water quality, and eventual exhaustion. All of these activities can change the character of the area’s water resources, potentially reducing their ability to provide for the future. Over the next two decades, population growth and migration will add an estimated 1.3 billion new urban residents who will require sanitation services (Bartone, 1994). Of these, 25 percent will live in megacities with populations of over 10 million. The growing periurban areas present a serious public health and environmental problem that will not be solved by traditional approaches to water and wastewater planning. Given these circumstances, how can the delivery of water and wastewater services be improved and expanded? The challenge is great. Water and wastewater service providers, health institutions, municipal and national governments, community organizations, and external aid agencies need to work together to improve incrementally the health, productivity, and quality of life of megacity residents. We turn now to some approaches by which this can be accomplished. APPROACHES TO IMPROVED SERVICES Improved Sanitation Progress in improving public health requires parallel and integrated improvements to drinking water supplies, wastewater management, and other aspects of sanitation. Sanitation is defined as the management of environmental conditions and the provision of services to prevent and control the spread of disease and enhance the welfare and well-being of human populations. Sanitation encompasses a wide range of activities, including the safe disposal of human and animal excreta and other domestic wastes; personal cleanliness; proper food handling; animal vector control; air quality control; proper management of wastes from urban commercial, industrial, and agricultural activities; and provision of a safe, sufficient, and convenient supply of water for household and other community needs.

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the context of megacity needs may lead to novel technological approaches that are less expensive to build and operate and more compatible with the needs and capabilities of the user communities. Innovation may be essential to addressing the needs of areas that have been difficult or impossible to serve under existing arrangements. Innovation is defined here as the first adoption by a culture or society of a method for providing goods and services that the society uses. Thus, innovation involves not only what is new, but also what is locally new. Innovation involves aspects of technology, organization, community, and financing. Many of the informal or squatter settlements lack authorization, land ownership, public rights of way, public services, and reasonable access. Incomes are low, living conditions are harsh, and illness and disease are widespread. Conventional water and wastewater technologies are at least inefficient under these conditions, and may be completely unfeasible. New approaches are clearly needed. Advances in hydraulic theory and technology, as well as experience, have provided the basis for modifications in the standards governing certain design parameters for conventional sewerage. The result has been a variety of sewerage systems that provide service levels similar to those of conventional sewerage at a fraction of the cost (Wright and Bakalian, 1990a). Some examples include flat gradient sewerage using smaller-diameter pipes; condominial sewerage; and other modifications to minimum depth, minimum slopes, minimum diameters of pipes, and the spacing and location of manholes. Solids-free sewerage (also known as small-bore sewerage) uses an interceptor tank to retain solids (Wright and Bakalian, 1990b). The tank is located between the house sewers and the rest of the system and allows flatter slopes and smaller diameters for sewer pipes. The key question for these and other alternatives is whether the lower capital costs would be offset by higher costs from operation and maintenance of the system. The suitability of alternative sewer systems needs to be demonstrated on a case-by-case basis for high-density urban areas. Consideration should be given to the development of strategies that foster continuous incremental improvements in the provision of water supply and wastewater services, especially for the poorly served communities within the metropolitan region. Planning should consider the local ability to finance, operate, and maintain the system; the potential for building institutional capacity; the need to upgrade systems to accommodate future population growth; and the community’s long-term vision of a high-performance system. As discussed earlier, planning for drinking water and wastewater services should be well integrated with other health and nutritional programs. The effective application of technology depends on the existence of carefully considered performance criteria that are appropriate to the megacities of the developing world. The continued use of effluent discharge standards borrowed from industrialized countries may hinder, rather than promote, meaningful innovation. Many of these standards simply reflect the capability of conventional technology rather than the needs of a particular environment or population. Adoption of such standards effectively precludes consideration of novel applications of technology, since the latter approaches will not necessarily produce the same results as conventional processes. An alternative is to apply performance criteria,

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which describe the desired effects on human health (reduced exposure to pathogens), the environment (ecosystems to be protected), and human activity (human uses of the environment). Most industrialized countries rely on technology-based standards rather than performance criteria. A critique of U.S. policy has indicated that this approach effectively discourages technological innovation, does not allow for regional differences, and has prevented the development of cost-effective water quality management programs (National Research Council, 1993a). On the other hand, the development and implementation of technology-based standards require less institutional competence than most alternatives. It is important that developing countries consider the pros and cons of any regulatory approach, rather than simply following the lead of industrialized countries. It must also be remembered that many megacities are especially vulnerable to natural hazards, such as floods, earthquakes, and high winds. The larger and more unplanned the city, the more difficult it is to organize rescue and respond to disaster. In the event of a natural disaster, the water and wastewater infrastructures are susceptible to blockage and rupture. The result can be contamination of water supplies and the spread of infectious disease. Thus planning for natural hazards should be part of any program to improve water and wastewater services (Institute of Civil Engineers, 1995). Given the right incentives, the private sector can often respond by creating new technologies that meet the needs and opportunities of megacities. In Japan, the private sector is creating and installing a new generation of technologies for water and wastewater treatment in smaller rural communities. The availability of capital in Japan has permitted joint government-industry efforts to research and develop new technologies, such as hybrid treatment reactors (combined activated sludge and biofilm), anaerobic treatment processes, and microaerobic processes (Rittmann, 1996). Based on anticipated growth, the influx of capital, and the potential to enter the large Asian market, a French consortium is developing sophisticated drinking water technology for Macau, near Hong Kong. Unfortunately, the poorest megacities may not receive this kind of attention from the private sector because their consumer markets are less certain. The World Bank is experimenting with private sector involvement under difficult economic circumstances, and has reported progress in such places as the Republic of Guinea and the City of Abidjan, as mentioned in the preceding section (World Bank, 1994). Chile has passed legislation to decentralize the water sector and has changed incentives to encourage privatization (Lauria, 1993). The private sector is stimulated to develop and apply new technologies when there is a demand of adequate size and constancy. Additionally, regulatory or administrative barriers to new technologies must be minimized, and the need of the private sector to generate a return on investment must be accepted. There are many other examples of technology innovation that may be useful for megacities in specific situations. These include low-cost water hook-ups, automated and remote meter reading, and low-cost materials and technology for neighborhood water and sewer systems. The use of water to carry away human wastes could, in some situations, be

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replaced by nonwater options, such as the use of dry toilets and composting of wastes for agricultural or garden applications. 2 The sustainability of innovative water, wastewater, and other sanitation projects will depend on the availability of indigenous human resources, as well as financial capital. The cadre of technical experts in the developing world needs to be expanded. Such experts are especially important for merging specialized knowledge with local conditions, experience, and financial realities. They must be skilled as facilitators and able to handle the ambiguity of human decision making, as well as the discipline of technical information. Local experts are also needed to evaluate the suitability of technology that may be offered and promoted by private concerns through sophisticated marketing strategies. Water Conservation and Reuse Effective water resource management requires a holistic approach that considers an entire watershed or catchment area relative to water quantity, quality, and use. Water is a renewable resource that should be managed so that future generations can obtain the same benefits as those enjoyed by current users. Such a resource should have a future value that is, on average, not less than its value today. Water resources are complex systems serving many users in different ways. This is particularly true for surface water resources. Surface waters provide fish and wildlife habitats, supply water to humans and human activities, and support the movement of goods and people. Achieving sustainability requires that each use of a resource be evaluated in the context of all other uses and stresses, and that no use be permitted which adversely affects the capability to support future uses. It also requires institutions that can implement effective laws and regulations. Current surface water withdrawals may or may not have an impact on future use, but ground water withdrawals frequently do. A lack of control over industrial waste discharge and a lack of wastewater treatment invariably threaten the sustainability of surface and ground water resources. Too often, the surface waters are grossly polluted and unsuitable for any use except as a sink for more waste. Ambient water quality standards that are reasonable and appropriate to local environmental, social, economic, and cultural conditions need to be established and enforced (see National Research Council, 1993a). Ground water is a far more important resource than is often realized. Excluding the water locked in glaciers and icecaps, about 97 percent of the world’s fresh water is ground water, while streams, rivers, and lakes hold only about 3 percent (Bouwer, 1978). The potential for human pathogens and toxic contaminants to leach into ground water depends on 2   Note that this paper is not meant to provide an assessment of technology options, but merely to highlight their potential importance.

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many factors, such as the composition of soils and geologic materials, the depth of the water table, the recharge rate, and environmental factors that can influence the mobility or degradation of contaminants (National Research Council, 1993b). Once ground water has become contaminated, the prospects for remediation are uncertain and expensive. Moreover, remediation may require long time periods (in some cases centuries) because of the complex properties of the subsurface environment and the complex behavior of contaminants (National Research Council, 1994a). In-situ bioremediation is a technology that is gaining momentum, but careful evaluation is necessary to determine whether it works (National Research Council, 1993c). Moreover, the costs of remediation are high. The potential cost of ground water remedial activities in the United States may be as large as $750 billion in 1993 dollars over the next 20 to 30 years (National Research Council, 1993b). Thus comprehensive ground water research, monitoring, and protection programs will be cost-effective investments in sustainability (e.g., see National Research Council, 1993b; National Research Council, 1995). To identify multiple-use and temporal conflicts in water resource allocation, it is necessary to take an integrated approach to the planning and management of the resource, and where appropriate, within a defined watershed or catchment area (see National Research Council, 1993a). Planning must consider all activities, present and future, within that region. Integrated management can be understood to address two outcomes: (1) the systematic allocation of resource services among competing users in the same time period, and (2) the consequences of that allocation for future availability and allocation of resource service flows. The criteria governing the first outcome typically include such things as economic efficiency, equity, fairness, and existing property rights. The second outcome addresses the issue of sustainability and fairness to future generations. Conservation of water resources should be a priority for all megacities, not only those that are located in arid or semiarid climates. In many megacities, a significant amount of water (reportedly 40 percent or more in some cases) leaks from the system or is otherwise unaccounted for because of poor metering, theft, or accounting errors. Together with proper maintenance and metering, water conservation requires changing people’s behavior through voluntary or involuntary demand management measures. Involuntary policy tools include water rationing, retrofitting of low-flow plumbing equipment, new construction codes, and water reuse regulations. Voluntary policy tools, in contrast, focus on the way people are charged for water and the use of public education campaigns. Voluntary tools have been less commonly utilized, but have the potential to be more cost-effective. The institution of appropriate water rates requires that users first be metered, which also reduces lost and unaccounted-for water. Tariff design must take into account the principles of cost recovery, demand (i.e., what people are willing to pay), fairness, and equity. As cities grow, water for urban uses becomes increasingly valuable as compared with other uses, such as agriculture. Water transfers, frequently a major component of water resource management, can involve the diversion of water to a new location or a change in the type of water use. When water is viewed as a commodity, its allocation can be driven by market forces, and these forces can act to enhance the efficiency of its use. However, water markets cannot be expected to resemble more conventional markets for a variety of historical, cultural, and ethical reasons. As with any policy option, there are benefits and

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costs. The recognition and protection of third-party interests are essential if water transfers are to meet their potential to satisfy new demands (National Research Council, 1992). Another means of conserving a community’s potable water supply is the practice of water reuse, which involves reclaiming industrial or municipal wastewater for the many nonpotable urban uses in a city. In this sense, reclamation and reuse of municipal wastewater represents a significant source of water, one that will become increasingly cost-effective. Nonpotable reuse applications for reclaimed municipal wastewater may include agricultural irrigation, ground water recharge (replenishment, salt water intrusion barrier, subsidence control), recreational uses (impoundments, lakes, fisheries, snowmaking), and general urban uses (fire protection, toilet flushing). Planning for new urban developments should consider the potential for incorporating water reuse in their design. The major public health concern associated with most uses of reclaimed water centers around infectious agents and the possible spread of disease among the human population. However, the health risk will be minimal if the wastewater is properly treated prior to use. The characteristics of the source water and the intended use of the reclaimed wastewater dictate the type and degree of treatment that must be provided in reclaiming municipal wastewater for nonpotable reuse (see National Research Council, 1982, 1994b; U.S. Environmental Protection Agency, 1992).

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