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What is the Safe Water System (SWS)?
Why was the SWS developed?
Who is the SWS for?
Where has the Safe Water System (SWS) been used?
How is a SWS started?

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Where has the Safe Water System been used?

Project Partners

  • CDC
  • Agha Khan University
  • Procter and Gamble Company
  • HOPE

Target Populations/Location

  • Low-income families living in squatter settlements in Karachi

Project Design

  • Research project objectives:
    • Determine the impact of the SWS on diarrheal disease incidence
    • Determine which etiologic agents the SWS prevents Identify modifications necessary to adapt SWS to Pakistan’s context
    • Function as a demonstration project to use to attract funding for broader SWS intervention in the country.

Intervention Elements

  • Locally available, commercial sodium hypochlorite disinfectant
  • The CDC safe water storage vessel
  • Community organization
  • Health education

Project Implementation Date

  • October 1997

Results of Project Evaluation

  • An inexpensive home-based water storage and decontamination system to improve drinking water quality in a low-income neighborhood of Karachi was pilot tested. Forty-seven households received a 20-liter plastic water storage vessel with a narrow neck, lid, and high-quality spout to prevent recontamination and a regular supply of diluted hypochlorite solution in 10 ml single-use bottles. Household members were instructed to fill the vessel with water, add one bottle of dilute hypochlorite, and use the water for drinking. Twenty-fivecontrol households were recruited. Water samples were evaluated at baseline and in unannounced follow-up visits 1,3, 6 and 10 weeks later. Baseline drinking water samples among households who received the vessel were contaminated with a mean 9397 cfu/100 ml of thermotolerant coliforms compared with a mean 10,990 cfu/100 ml among controls. After intervention there was a mean 99.8% reduction in concentration of thermotolerant coliforms in drinking water samples among the vessel households, compared with an 8% reduction in controls. All 47 households who received the vessel reported liking it. In a highly contaminated environment, a specifically designed water storage container and in-home water chlorination was acceptable to the community and markedly improved water quality.
  • A study currently in the field is evaluating the effect of the SWS on diarrhea incidence.

For More Information




Centers for Disease Control and Prevention
National Center for Infectious Diseases
Division of Bacterial and Mycotic Diseases
Foodborne and Diarrheal Diseases Branch

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