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close this bookGlobal Water Supply and Sanitation Assessment 2000 Report (UNICEF - WSSCC - WHO, 2000, 90 p.)
View the document(introduction...)
View the documentForeword by the Director-General of WHO and the Executive Director of UNICEF
View the documentForeword by the Chairperson of the Water Supply and Sanitation Collaborative Council
View the documentPreface
Open this folder and view contents1. The Global Water Supply and Sanitation Assessment 2000
Open this folder and view contents2. Global status
Open this folder and view contents3. Sector performance
Open this folder and view contents4. Water supply and sanitation in large cities
Open this folder and view contents5. Challenges, future needs and prospects
Open this folder and view contents6. Africa
Open this folder and view contents7. Asia
Open this folder and view contents8. Latin America and the Caribbean
Open this folder and view contents9. Oceania
Open this folder and view contents10. Europe
Open this folder and view contents11. Northern America
View the documentReferences
View the documentAcknowledgements
View the documentAnnex A: Methodology for the Global Water Supply and Sanitation Assessment 2000
View the documentBack Cover

Annex A: Methodology for the Global Water Supply and Sanitation Assessment 2000

Monitoring the population with access to improved drinking-water supply and facilities for improved sanitation has posed major problems. A review of water and sanitation coverage data from the 1980s and the first part of the 1990s showed that the definition of safe, or improved, water supply and sanitation facilities sometimes differed not only from one country to another, but also for a given country over time. Indeed, some of the data from individual countries often showed rapid and implausible changes in level of coverage from one assessment to the next. This indicated that some of the data were also unreliable, irrespective of the definition used. Furthermore, coverage data were based on estimates by service providers, rather than on the responses of consumers to household surveys, and these estimates can differ substantially. For example, public water utilities are unlikely to consider private household wells, and little may be known officially of householders' own sanitation facilities.

The Assessment 2000 marks a shift from gathering provider-based information only to include also consumer-based information. The use of consumer-based information was discussed in the previous Joint Monitoring Programme report.1 The current approach aims to take a more accurate account of the actual use of facilities, and of initiatives to improve facilities taken by individuals and communities, which in some cases might not be included in official national water supply and sanitation statistics. By using household surveys, this approach also provides more information on breakdowns and service deficiencies, which might render the facilities unusable after they had been installed, and on service technologies. A drawback of this approach is that household surveys are not conducted recurrently in many countries. Another problem is the lack of standard indicators and methodologies, which makes it difficult to compare information obtained from different surveys.

1 Water supply and sanitation sector monitoring report - sector status as of 31 December 1994. Geneva, World Health Organization, 1996 (WHO/UNICEF joint report).

Data collection

Data were collected from two main sources: assessment questionnaires and household surveys. Assessment questionnaires were sent to all WHO country representatives, to be completed in liaison with local UNICEF staff and relevant national agencies involved in the sector. Initially, assessment questionnaires were distributed with detailed instructions on the process by which it was to be completed. WHO staff (or, where appropriate, consultants or government officers) were requested to liaise with the local UNICEF country office and with the various national agencies involved in providing water supply and sanitation services.

Those completing the questionnaire were first asked to compile an inventory of existing population-based data on access to water supply and sanitation, particularly national census reports, Demographic Health Surveys (DHS) conducted by Macro International and funded by the United States Agency for International Development, and UNICEF's Multiple Indicator Cluster Surveys (MICS). The coverage figures returned by each country with the endorsement of government officials were to be based, as far as judged appropriate, on the estimates from such surveys and recent censuses.

Household survey results were collected and reviewed, including the DHS and MICS results. The DHS and MICS are national cluster sample surveys, covering several thousand households in each country. The samples are stratified to ensure that they are representative of urban and rural areas of each country. They collect information, at household level, on the main source of drinking-water used, as well as the sanitation facility. In most cases, each household is asked to identify the type of water source or sanitation facility they use from a list of technologies, such as piped in-house water supply, private well, borehole or protected spring. These surveys have therefore collected data from consumers on the faculties which they actually use, including those which they have installed themselves, such as private wells or pit latrines. Estimates by services providers often neglect to check that their facilities are functioning, let alone used; moreover, service providers are usually unaware of self-built facilities, or even systems installed by small local communities. Household surveys therefore provide an important step forward in obtaining more accurate coverage information for the sector.

Definitions of access

The following technologies were included in the assessment as representing “improved” water supply and sanitation:

Water supply


Household connection

Connection to a public sewer

Public standpipe

Connection to septic system


Pour-flush latrine

Protected dug well

Simple pit latrine

Protected spring

Ventilated improved pit latrine

Rainwater collection

The following technologies were considered “not improved”:

Water supply


Unprotected well

Service or bucket latrines

Unprotected spring

(where excreta are manually removed)

Vendor-provided water

Public latrines

Bottled water2

Latrines with an open pit water

Tanker truck-provided

2 Considered as “not improved” because of concerns about the quantity of supplied water, not because of concerns over the water quality.

The assessment questionnaire defined access to water supply and sanitation in terms of the types of technology and levels of service afforded. For water, this included house connections, public standpipes, boreholes with handpumps, protected dug wells, protected springs and rainwater collection; allowance was also made for other locally-defined technologies. “Reasonable access” was broadly defined as the availability of at least 20 litres per person per day from a source within one kilometre of the user's dwelling. Types of source that did not give reasonable and ready access to water for domestic hygiene purposes, such as tanker trucks and bottled water, were not included (Box A.1). Sanitation was defined to include connection to a sewer or septic tank system, pour-flush latrine, simple pit or ventilated improved pit latrine, again with allowance for acceptable local technologies. The excreta disposal system was considered adequate if it was private or shared (but not public) and if it hygienically separated human excreta from human contact.


In developing the methodology of the Assessment 2000 there was considerable discussion regarding the acceptability of sources such as bottled water and vendor-provided supplies (including tanker-truck supplies). These categories were considered inadequate. In some circumstances vendor-provided supplies may provide adequate minimum volumes although evidence suggests that this is rarely the case. The volumes secured from vendor sources may be severely limited by cost and experience suggests that water quality is often poor. Bottled water alone does not provide adequate volumes of water for domestic use and water for other domestic purposes must be secured from other sources. There may be circumstances in which the combination of readily available (but non-potable) water for domestic use, plus high quality and affordable bottled water for drinking, may be adequate. This combination of circumstances was not considered common and its omission is estimated to have had a negligible impact on regional and global statistics. The table below indicates the extent to which bottled, vendor-provided and tanker-truck water contribute to supply worldwide. It should be recalled that a large proportion of bottled water will be consumed by individuals who have access to improved water in their households.



Source of water

Percentage of the urban population that consumes bottled or vended water

Percentage of the rural population that consumes bottled or vended water



Tanker truck













Dominican Republic


Bottled water





Tanker truck





Tanker truck





Bottled water





Bottled water





Tanker truck



Libyan Arab Jamahiriya


Tanker truck




















Bottled water



Syrian Arab Republic


Tanker truck





Bottled water/demi john





Bottled water



Source: JMP Databook 2000 (in press)

Access to water and sanitation, as reported below, does not imply that the level of service or quality of water is “adequate” or “safe”. The assessment questionnaire did not include any methodology for discounting coverage figures to allow for intermittence or poor quality of the water supplies. However, the instructions stated that piped systems should not be considered “functioning” unless they were operating at over 50% capacity on a daily basis; and that handpumps should not be considered “functioning” unless they were operating for at least 70% of the time with a lag between breakdown and repair not exceeding two weeks. These aspects were taken into consideration when estimating coverage for countries for which national surveys had not been conducted. However, they were not taken into consideration when estimating national coverage using survey data, on which the report is primarily based.

In some regions, where higher levels of service were more prevalent, there was a tendency by national reporting authorities to set stricter requirements for access compared to other regions. These tendencies may be reflected in the data and should be taken into account when the national estimate is based exclusively on figures collected through the assessment questionnaire.

Definitions of urban and rural

The Assessment 2000 did not provide a standard definition of urban or rural areas. Instead, the questionnaire asked for the countries' own working definition of urban and rural. Similarly, when using household survey data, definitions predetermined by those responsible for the survey were accepted.

Data analysis

Electronic country files were prepared presenting all of the information collected from the global assessment questionnaire and existing survey data. The definitions of access to improved water supply and sanitation were consolidated across the two types of information source.

For each country, coverage estimates from surveys were plotted against the year in which the corresponding survey had been carried out. Four separate charts were used to show coverage by year in the period 1980 - 2000, one each for urban water, rural water, urban sanitation and rural sanitation. All other sources of data were also plotted in these charts for comparison and context, but were labelled differently. Some surveys were part of this latter category because the classification of sources or facilities was insufficient. Unfortunately, some surveys did not provide all of the information needed, not having been designed specifically to collect information about water and sanitation. For example, in many cases wells are reported without any indication of whether or how they are protected. The situation is often similar for springs.

For charts where coverage estimates from surveys were considered adequate, a line was drawn on each chart that, in the opinion of the review group, best fitted the survey estimates over the period 1990 - 2000. If the estimate from this best-fit line differed substantially from the 2000 estimate provided by the country, the country was asked to review its estimate in the context of the data displayed on the chart. The resulting discussions sometimes led to modification of the chart, sometimes to changes of the national estimate. Where no resolution could be obtained, the 2000 estimate derived from the survey data was used.

In a small number of charts there were insufficient survey data to derive a 1990 estimate. In these cases, an estimate for 2000 only was used. For countries where there were inadequate survey data, the national estimate for 2000 provided by the country was used. Particular care was taken with the larger developing countries, as the conditions in those countries have a disproportionate effect on the global and regional averages. In particular, the 40 most populous developing countries - which account for some 90% of the population of the developing world - were the subject of special attention. These forty countries are:

Islamic State of Afghanistan
People's Democratic Republic of Algeria
Argentine Republic
People's Republic of Bangladesh
Federative Republic of Brazil
People's Republic of China
Republic of Colombia
Democratic People's Republic of Korea
Democratic Republic of the Congo
Arab Republic of Egypt
Federal Democratic Republic of Ethiopia
Republic of Ghana
Republic of India
Republic of Indonesia
Islamic Republic of Iran
Republic of Iraq
Republic of Kenya
Republic of Madagascar
United Mexican States
Kingdom of Morocco
Republic of Mozambique
Union of Myanmar
Kingdom of Nepal
Federal Republic of Nigeria
Islamic Republic of Pakistan
Republic of Peru
Republic of the Philippines
Republic of Korea
Kingdom of Saudi Arabia
Republic of South Africa
Democratic Socialist Republic of Sri Lanka
Republic of the Sudan
Kingdom of Thailand
Republic of Turkey
Republic of Uganda
United Republic of Tanzania
Bolivarian Republic of Venezuela
Socialist Republic of Viet Nam
Republic of Yemen

Methods for developing regional coverage figures

Estimates of percentage coverage for a region are based upon available data from the reporting countries in the region. When no data were available for countries in a region, estimates were extrapolated from countries in the region for which data were available. Such extrapolation, however, is used only to compute regional statistics: any country data reported in this assessment are based on reports for the country concerned.

In summary, while the type of water source and the type of excreta disposal facility can be associated with the quality of water and the adequacy of disposal, respectively, they cannot adequately measure population coverage of safe water or of sanitary excreta disposal. Hence, the coverage estimates presented in this report represent the population covered by improved water sources and improved sanitary facilities.