Water distribution has to be thought from the source to the consumer's tap. A correct distribution system has to be well-planned and designed beforehand, and adapted maintenance performed while in use. Many transportation systems are possible (piped with the use of different materials and techniques, non-piped), and have to be carefully chosen, dimensioned, operated and maintained in order to use well-adapted, efficient, and safe solutions.
The water allocation of human settlements concerns both water quantity and quality. Providing accountable, efficient water and sanitation services along with sustainable and affordable access to safe water is one of the big challenges of our time. Similar living conditions can be found in many developing countries. Within the countries, varied socio-economic clusters exist, consisting of people living in large metropolis, bigger cities, medium cities, small towns, villages, small tribal settlements or isolated housings. The concentration of people in large urban regions brings an increasing pressure on water resources, while tribal settlements may be located in remote areas difficult to reach.
The methods for drinking water transport to the populations living in these different conditions can be synthesised with three main systems:
Such networks exist almost all over the world, varying with the local conditions. While in more developed systems, transport and further distribution bring the water directly into the households, in developing regions, taps are installed on community level and manual carrying by the users or a private system distributing the water in reservoir trucks brings the freshwater from these centralised taps to the users.
Large pipelines normally consist of fabricated steel pipes along with provision for necessary coatings like cement, mortar, epoxy, etc. Smaller conveyance systems consist of transportation of drinking water through cast iron, ductile iron, PVC and such other pipes. Using brick and stone ducts to transport drinking water should be avoided to prevent leakage (see also piped water distribution).
Leakage in the conveyance and distribution system generally implies large losses of water during the transport from its source to the user (see also leakage control). Awareness on drinking water scarcity and the effects of leakage are often lacking. Total leakage can account up to half of the water produced. Too few cities make adequate efforts for leakage control through systematic leakage detection and management programs. In urban poor populations, water sometimes happens to be stolen through illegal piping or water tapping, leading to large quantity of non-revenue water.
Gravity distribution networks allow transporting the water in the distribution system without the need of energy, but this is not possible everywhere. Sometimes, the elevations of the impounding reservoirs are such that raw water can be brought by gravity to treatment plants, but once treated water needs to be pumped to elevated master reservoirs from where it can be conveyed to various reservoirs and further to consumers by gravity. In many cases, in one or another stage, water needs to be pumped in order to distribute it in the piping network. Hence, there is a great need for optimisation of energy consumption for the pumped waters (see also energy optimisation in water distribution systems). For rural water supply, however, energy is not always available and distribution depends on gravity and non-piped transport (buckets or trucks) only. Non-piped transport of water in rural areas, often done by women or children, has many social implications and deep efforts are needed to avoid the ill effects of such methods on the society. Decentralising water catchment, treatment and distribution can help to simplify the required conveyance system and thus also the related costs, energy and operation and maintenance requirements (see also decentralisation of water distribution networks). A few non-governmental organisations are trying to create awareness through the construction of low cost water storage tanks to store either rain water or water supplied by local authorities.
In developing countries, water supply is often not a 24-hours service but rather an intermittent one. This is inconvenient for private users or local industries and should be avoided, but it might also be useful as a short-term measure to reduce water consumption and prevent water shortages, as long as adapted precautions are taken (see also intermittent water supply). A necessary measure to control water use and to finance water distribution infrastructure is water pricing or water metering (see also economic measures). This is also a useful tool to raise awareness on the value of water, and of its need for being preserved.
Capacity building (see also water distribution software) within the utilities allows them to adapt to the changing needs of the served population. Public-public or controlled public-private partnerships can also lead to an improvement of the water distribution service, either in piped systems or via the distribution of water in containers (e.g. reservoir trucks, water kiosk for drinking water, see also economic issues in the background section). The water distribution can also be completely privatised following the rules of the market. However, considering access to water as a human right (see also the right to water and sanitation), a collaboration with the government seems compulsory as it is the responsibility of governmental agencies to provide, be it on the initiative of non-governmental organisation, a legislative framework (guidelines and policies) for both public or private water distribution systems (see also water quality standards).
BRIKKE, F.; BREDERO, M. (2003): Linking Technology Choice with Operation and Maintenance in the context of community water supply and sanitation. A reference Document for Planners and Project Staff. Geneva: World Health Organization and IRC Water and Sanitation Centre. URL [Accessed: 30.03.2010]. PDF
This document is addressed to planners and staff of water supply and sanitation projects on household and community level. The reader is guided through the main steps of informed choices regarding the main proven technologies for water supply, purification and water treatment at household and community level. Each technology is described in a small factsheet, regarding its functioning, actors and their roles, the main operation and maintenance (O&M) requirements and problems, which can occur.
This manuals is primarily aimed at project managers, engineers and technicians, but can also be used by others. It contains information on project development in regard to drinking water supply and concrete tools for project management.
Guide and sourcebook on urban water supplies, focusing on Asia. It looks at problems and solutions related to water resources management, private sector participation, non-revenue water… The book proposes a new approach to the development and management of water supplies, based on transparent government policy and regulation, and the involvement of civil society.
SDC (Editor); SWISS RE (Editor); SECO (Editor) (2005): Public-private Partnerships for Water Supply and Sanitation. Policy Principles and Implementation guidelines for Sustainable Services. Bern: SDC. URL [Accessed: 26.08.2010]. PDF
This document contains a summary of tools for public-private partnerships in the water supply and sanitation sector. It describes a summary of policy principles and implementation guidelines for sustainable services.
WSP (Editor) (2008): African Water Utilities Regional Comparative Utility Creditworthiness Assessment Report. Kenya: Water and Sanitation Program - Africa Regions. URL [Accessed: 26.08.2010]. PDF
This report compares different water utilities in Africa, in regard to their size, operation, efficiency, and also debt and liquidity. Yet, it also contains more general information, such as an economic and regulatory overview of water utilities (water utility business models, performance agreements, management, availability of water and sanitation, regulatory environment, tariff structure etc.).
WATERAID TANZANIA (Editor) (2009): Management for Sustainability Practical lessons from three studies on the management of rural water supply schemes. Dar es Salaam: WaterAid Tanzania. URL [Accessed: 26.08.2010]. PDF
Practical lessons from three studies on the management of rural water supply schemes in Tanzania.
CPHEEO (Editor) (2005): Manual on Operation and Maintenance of Water Supply Systems. New Delhi: Central Public Health and Environmental Engineering Organization (CPHEEO), Indian Ministry of Urban Development. URL [Accessed: 17.08.2010]. PDF
This manual is intended for the managers and technicians in charge of the operation and maintenance of the urban drinking water supply systems. It is a guide to strengthen the technical, operational and managerial capabilities required of the concerned personal in order to maintain acceptable norms of quantity, quality, reliability and cost.
In this technical note, the delivery systems normally considered for rural villages are described in terms of three levels of service. These depend on the constructing, operating and maintenance costs and techniques, and their impact on the consumer's health and convenience.
http://www.rwsn.ch [Accessed: 16.08.2010]
Website of the Rural Water Supply Network. RWSN focuses on the following four flagship themes, with an emphasis on sub-Saharan Africa: Self supply, Cost-effective boreholes, Sustainable rural water supplies, and Hand pump technologies, and contains a lot of information regarding all these aspects.
http://www.irc.nl/ [Accessed: 16.08.2010]
Web page of the International Water and Sanitation Centre (IRC) with several publications on water supply systems operation and maintenance.