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Centers for Disease Control and Prevention. CDC twenty four seven. Saving Lives, Protecting People
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This historic 1941 diagram, which had been digitally enhanced, illustrated a method of altering tank-type flush toilets, to prevent back-siphoning, or the sudden loss of pressure within a plumbing system, allowing dirty water to be sucked into the clean water supply pipes. Such a phenomenon could involve just the plumbing in a single house, if it was on its own well, or it could occur inside a municipal water system. The focus of these images was on protecting water supplies from bacterial contamination due to incorrect disposal of waste, in order to prevent water-borne diseases. The descriptive information accompanying this drawing referred to a governmental publication, which contained instructions describing how to correctly place, and build such a device. The specific citation was, “Minnesota Department of Health, Division of Sanitation,
Manual of Water Supply Sanitation
, 1938, Section 8, p. 14”.
Click here for hi-resolution image (34.18 MB)
CDC/ Minnesota Department of Health, R.N. Barr Library; Librarians Melissa Rethlefsen and Marie Jones
Minnesota Health Department
Minnesota Health Department; R.N. Barr Library
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Environment and Public Health
Midwestern United States
- This image is in the public domain and thus free of any copyright restrictions.
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