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Water Engineering and Development Centre

Resource details

How safe is safe?: A concise review of the health impacts of water supply, sanitation and hygiene

Author(s): Hunt, Caroline

Publisher: LSHTM | WEDC
Place of publication: London and Loughborough
Year: 2001

Series: WELL Studies in Water, Sanitation and Environmental Health Task 509
Collection(s): WELL


The WHO /UNICEF Joint Monitoring Programme (JMP), to whose year 2000 Global Assessment WELL provided technical support, has collected and reviewed population-based water supply and sanitation coverage data for most of the countries in the world. This report reviews the epidemiological and related literature on safety of different levels of service and different technologies for providing service. Methodological difficulties in estimating health risk are introduced. Coverage is for the first time derived from consumer-based data taken from large nationally representative household surveys.

In the first section, there are a number of models for understanding how water supply, sanitation and hygiene affect health. They are as follows:

  • Classifications of water-related and excreta-related infections. It groups water related infectious diseases by broad routes of transmission
  • The F-diagram. It is widely used as model of faecal-oral disease transmission
  • The public and private domains. This model complements the move away from the traditional engineering approach to the public health. It acknowledges the importance of household practices and behaviour.
  • Hygiene behaviour. There has been increasing emphasis on hygiene behaviour in the literature in the last ten years.

The second section of the report focuses on assessment methodologies and difficulties. Most epidemiological studies into the relationship between water supply, sanitation, hygiene and health are observational. Problems with these studies are around lack of control for outcomes and recall bias.

The third section of the report focuses on determinants of health impact of water supply and sanitation. These are access and use, treatment and maintenance, seasonality, pathogen specific factors, source of water, urban-rural differences and situations of conflict and natural disasters.

Health impact