Water Distribution Overview

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:

• Construction of impounding reservoirs on the rivers and intake wells connected to a network of conveyance system up to the cities and further distribution system within the cities along with service reservoirs.
• Construction of small ponds with dam including intake wells and further pipelines up to small towns and villages.
• Exploitation of surface or spring water and construction of small ponds or reservoirs in rural areas and the villagers carrying the contained water from such ponds to the residencies with buckets or private entrepreneur transporting the water in vessels or reservoir trucks to sell it to the households.

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).