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Water supply indicators

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There are many indicators of water supply, storage, and use. This discussion will focus only on those basic indicators most commonly measured quantitatively in newly displaced populations. See the Sphere Project manual (click here to open document)pages 63-70 for a discussion of other water supply indicators.

Amount of water available

Often relief agencies provide for the water needs of an emergency-affected population by drilling wells, by pumping and treating water from surface sources (such as streams or lakes), or by bringing water by truck. This indicator is usually expressed as litres of water available per person per day. It should include only "safe" water, that is, water from a protected well, borehole, or spring or water which has been adequately treated to eliminate disease-causing organisms.

The agencies responsible for providing water should keep track of the amount of water supplied. From these programme data and an estimate of the population, the amount of water provided per person per day can be calculated. This indicator can also be measured in a survey by asking household respondents how much water they use. However, care must be taken to use a standard measure of volume which is readily understood by all survey respondents.

Both the Sphere Project and the UN High Commissioner for Refugees (UNHCR) recommend a minimum of 15 litres of water by supplied per person per day. UNHCR further stipulates that 7 litres per person per day is the absolute minimum amount to survive.

Distance to water source

Often water distribution points are set up throughout the camp or population. (Click here for a photo of a tap stand water distribution site in Kabumba Camp in Goma, Zaire). Sometimes these access points are wells or boreholes. Sometimes water is piped or trucked to spigots from which individuals can get water. (Click here for a photo of a water truck filling storage tanks in Kabumba Camp in Goma, Zaire). The distance between the nearest water access point and each household is one indicator of the access to safe water.

This indicator can be measured in a survey, but it requires actually measuring the distance between each selected household and the closest water access point. Survey respondents probably cannot accurately estimate this distance. However, having survey teams measure the distance may be quite time consuming in emergency assessment surveys. Another way to measure this indicator is to map the camp, including the water access points. This will not actually produce an average distance, but you can tell if there are households too far from a water access point.

In order to reduce the time and energy required for fetching water and to encourage the use of safe water sources, the Sphere Project states that water access points should be a maximum of 500 meters from every household.

Time needed to fetch water

There are often long queues at water access points because it takes time to fill containers. (Click here for a photo of a water queue in Mugunga Camp in Goma, Zaire). This is especially true if water is available only for a short period each day. As a result, people may have a water access point nearby, but spend a long time fetching water.

Although this information could be obtained from interview questions during a survey, respondents may not be able to give precise enough answers. Populations in less-developed countries often do not keep clock time. This indicator can probably better be estimated by observing the queue at one or more water access points and timing how long it takes someone who just joined the queue to get to the tap and fill their water container. Organizations responsible for supplying water should measure this wait time frequently to be sure it is not too long.

Again, in order to reduce the time required for fetching water and to encourage the use of safe water sources, the Sphere Project recommends that no more than 15 minutes is spent waiting in queues at water access points.

Water quality

Good quality water is necessary to ensure that water-borne disease transmission is minimized or eliminated. Many diarrheal diseases may be spread by water, including cholera, dysentery, viral diarrhoea, and others. Surface sources are, by definition, unsafe because of their potential for contamination with disease-producing organisms. Even well water from inadequately protected wells is unsafe to drink. (Click here for a photo of an open, contaminated well in Monrovia, Liberia).

Water quality testing requires laboratory assessment. Fortunately, there are cheap, easy, and fast methods of testing water for bacterial organisms or stool contamination. Chlorine concentration can also be measured quite easily; however, both these methods require someone with the appropriate skills and experience. This task again should be the responsibility of the organization supplying water.

The Sphere Project recommends than water for human consumption should have a faecal coliform count of 0 organisms per 100 ml of water. The presence and concentration of faecal coliforms is a measure of the extent of contamination with human or animal stool. The Sphere Project also recommends that for water which is treated, the free chlorine residual at the tap is at least 0.5 mg/l of water and that the turbidity is less than 5 NTU.