Development of a toolbox to assess microbial contamination risks in small water systems

Individual and small water systems account for the majority of waterborne disease outbreaks recorded in the United States each year. To address this problem a project was undertaken to develop a comprehensive self-assessment toolbox that could be used by small water system personnel to determine where their system has the greatest potential risks from microbial contamination. The toolbox components consist of: (1) a survey that asks specific questions; (2) a ranking tool that computes numerical scores for water system components based on survey answers; (3) comments and results from the ranking tool; (4) a guidance document to help the user understand why certain conditions may represent a risk; and (5) instructions for using the toolbox. A unique feature of the ranking tool is the ability to input expert opinion in the form of scores for each answer and weighting factors. Weighting factors are derived using ranked, pairwise comparisons, and then used to determine numerical scores for system components. Toolbox administrators are allowed to modify weighting factors used by the ranking tool application, thus allowing input of expert opinion.

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Design of Small Water Systems

10.21236/ada401999 ◽

1999 ◽

Author(s):

Albert J. Genetti ◽

Keyword(s):

Water Systems ◽

Small Water ◽

Small Water Systems

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Applying Economic Principles to Small Water Systems

American Water Works Association ◽

10.1002/j.1551-8833.1987.tb02843.x ◽

1987 ◽

Vol 79 (5) ◽

pp. 57-61 ◽

Cited By ~ 10

Author(s):

Robert M. Clark

Keyword(s):

Water Systems ◽

Small Water ◽

Small Water Systems

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Using Decision Trees to Predict Drinking Water Advisories in Small Water Systems

Opflow ◽

10.5942/jawwa.2016.108.0008 ◽

2016 ◽

Vol 108 ◽

pp. E109-E118 ◽

Cited By ~ 5

Author(s):

Heather M. Murphy ◽

Munir Bhatti ◽

Richard Harvey ◽

Edward A. McBean

Keyword(s):

Drinking Water ◽

Decision Trees ◽

Water Systems ◽

Small Water ◽

Small Water Systems

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An approach for developing a national estimate of waterborne disease due to drinking water and a national estimate model application

Journal of Water and Health ◽

10.2166/wh.2006.024 ◽

2006 ◽

Vol 4 (S2) ◽

pp. 201-240 ◽

Cited By ~ 78

Author(s):

Michael Messner ◽

Susan Shaw ◽

Stig Regli ◽

Ken Rotert ◽

Valerie Blank ◽

...

Keyword(s):

Drinking Water ◽

Environmental Protection Agency ◽

Water System ◽

Credible Interval ◽

The United States ◽

Water Systems ◽

Epidemiologic Studies ◽

Incidence Rates ◽

Waterborne Disease ◽

Public Water Systems

In this paper, the US Environmental Protection Agency (EPA) presents an approach and a national estimate of drinking water related endemic acute gastrointestinal illness (AGI) that uses information from epidemiologic studies. There have been a limited number of epidemiologic studies that have measured waterborne disease occurrence in the United States. For this analysis, we assume that certain unknown incidence of AGI in each public drinking water system is due to drinking water and that a statistical distribution of the different incidence rates for the population served by each system can be estimated to inform a mean national estimate of AGI illness due to drinking water. Data from public water systems suggest that the incidence rate of AGI due to drinking water may vary by several orders of magnitude. In addition, data from epidemiologic studies show AGI incidence due to drinking water ranging from essentially none (or less than the study detection level) to a rate of 0.26 cases per person-year. Considering these two perspectives collectively, and associated uncertainties, EPA has developed an analytical approach and model for generating a national estimate of annual AGI illness due to drinking water. EPA developed a national estimate of waterborne disease to address, in part, the 1996 Safe Drinking Water Act Amendments. The national estimate uses best available science, but also recognizes gaps in the data to support some of the model assumptions and uncertainties in the estimate. Based on the model presented, EPA estimates a mean incidence of AGI attributable to drinking water of 0.06 cases per year (with a 95% credible interval of 0.02–0.12). The mean estimate represents approximately 8.5% of cases of AGI illness due to all causes among the population served by community water systems. The estimated incidence translates to 16.4 million cases/year among the same population. The estimate illustrates the potential usefulness and challenges of the approach, and provides a focus for discussions of data needs and future study designs. Areas of major uncertainty that currently limit the usefulness of the approach are discussed in the context of the estimate analysis.

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