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NWRI Independent Advisory Panel Report



Review of California's Water Recycling Criteria for Agricultural Irrigation


Prepared for the California Department of Public Health (CDPH)

September 2012

Pub No. NWRI-2012-03

Download the Report (2.45-MB PDF, 172 Pages)





Report Description


The 2012 report, “Review of California’s Water Recycling

Criteria for Agricultural Irrigation,” was developed in response

to increased interest in expanding the amount of recycled

water used for agricultural purposes.


It specifically addressed the risk of exposure and infection

from waterborne pathogens, such as Cryptosporidium and

E. coli, due to the irrigation of a wide variety of food crops

using recycled water.


The report was prepared by a panel of nine experts jointly led by Robert C. Cooper, Ph.D., who is Professor Emeritus of the School of Public Health at the University of California, Berkeley, and Adam W. Olivieri, Dr.P.H., P.E., the Vice President of EOA, Inc., a public health and environmental engineering consulting firm based in Oakland, Calif.


Cooper has published more than 70 papers on water quality and infectious disease, while Olivieri is an expert on the technical and regulatory aspects of water recycling and public health risk assessment.


Key issues addressed by the panel include:



In the report, the panel includes responses to each of these issues, as well as provides suggestions to refining the State’s Water Recycling Criteria.


Among the conclusions, the panel stated that “current agricultural practices that are consistent with the [Water Recycling Criteria] do not measurably increase public health risk, and that modifying the standards to make them more restrictive will not measurably improve public health.”





panel photo

Members of the panel met at the CDPH facility in Richmond, California, in February 2012.

About the Panel


The panel included nine nationally recognized experts

in the fields of public health microbiology and virology, quantitative microbial risk assessment, public health infectious diseases and epidemiology, water reuse,

food safety and hazard analysis, agricultural practices, irrigation management, emerging contaminants

of concern (i.e., waterborne infectious agents),

and water and wastewater treatment effectiveness. 


Together, the panel has well over 150 years of

combined experience investigating water reuse

and potential public health issues.


While the panel was formed in 2008, it did not begin work until the spring of 2010.  Over a 2-year period, the panel held four meetings, a number of subcommittee meetings, and numerous conference calls.  The panel meetings included the opportunity for stakeholder input in clarifying the panel’s charge, exchange of information, dialog with the panel, and consideration of comments from SWRCB and CDPH staff on this draft report, which was prepared by the Panel and provides the results from the deliberations.


Member of the panel include:



Click here to read the panel biographies.



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