【正文】 nd startup costs. Subsidies are designed to reduce access barriers to which lowine groups are especially sensitive, such as initial connection, equipment, or installation charges. ?Customers pay for the use of services at least as much as is needed to meet operating and maintenance costs. Where domestic installations are involved, customers are also required to pay part of the investment cost, as a confirmation of economic demand for service and mitment to pay for service use. Consumption is subsidized only exceptionally and limited to small amounts of service regarded as essential. The design of subsidies is closely tied to the available service delivery mechanisms. Subsidies are channeled through the service supply chain in ways that aim at being neutral with respect to petition among service providers, service alternatives, and technologies. 2 Water supply Potable water and, to a lesser extent, sanitation services, are often a priority for rural munities. Willingness to pay for improved services depends on the distance to, and quality of, existing sources of water and sanitation facilities, as well as the consumers’ perceptions of the health threats of unimproved services. Solutions to improved water supplies in rural areas are almost always localized, the water supply (be it ground or surface water) and its treatment and distribution being provided in each munity as a standalone system. Network solutions only make economic sense in areas where water sources are scarce or expensive, or where munities are close to one another. For each water technology there are also service level options, which can range from shared facilities (public stand posts or munity hand pumps) to house connections (individual hand pump, yard tap, or inhouse plumbing). For sanitation services the choice of technology and service level depends on population size and concentration, water service level and consumption rates, and soil permeability. For most rural areas in developing countries, the appropriate solution will be an onsite sanitation system (latrine or septic tank). Piped sewer and wastewater treatment systems are sometimes installed in larger munities, but costs are high. After years of struggling to achieve sustainable rural water systems scattered in munities across the rural landscape, most countries have now shifted from centralized supplydriven service provision models to decentraliz