Western Growers Science is pleased to share a new peer-reviewed article published in the Journal of Food Protection: “A Review of Reclaimed Water Use for Irrigation of Produce Crops and Food Safety Aspects in the United States.”
The review was led by the Western Growers Science team in collaboration with Dr. Trevor Suslow of the University of California, Davis; Dr. Daniel Gerrity of the Southern Nevada Water Authority and the University of Nevada, Las Vegas; and Susan Leaman of iDecisionSciences.
As water availability continues to challenge agriculture, reclaimed or recycled water is receiving increased attention as a potential supplemental irrigation source. The article reviews the current regulatory and scientific landscape for using reclaimed water in fruit and vegetable production, including treatment approaches, microbial water-quality criteria, monitoring practices and irrigation considerations.
The review highlights that safe use of reclaimed water depends on more than treatment at the water reclamation facility. Storage and distribution systems, irrigation methods, potential contact with the edible portion of crops, harvest timing and on-farm water-management practices are all important considerations.
The article also identifies areas where continued research is needed, including treatment effectiveness against more resistant pathogens and the evaluation of emerging chemical constituents. This work provides a resource for growers, water providers, regulators, buyers and researchers as the industry continues to evaluate sustainable water-use options while maintaining confidence in produce safety.
What is reclaimed water?
Reclaimed water is treated as wastewater that is reused for a beneficial purpose. Depending on the intended use and applicable state requirements, treatment can include secondary treatment, filtration and disinfection. Requirements are generally more stringent when water may contact the edible portion of a crop.
Reclaimed water and produce irrigation
The review shows that reclaimed water may be used for food crop irrigation in some states, but allowable uses depend on state-specific requirements. Arizona, California, Colorado and Florida all have frameworks that distinguish allowable irrigation uses based on treatment level and crop-contact conditions.
For example, California allows its highest reclaimed-water category, disinfected tertiary recycled water, to irrigate food crops when water is expected to contact the edible portion of the crop. Other categories may be limited to crops where the edible portion is not contacted by the reclaimed water.
What does the research say about safety?
The article reports that secondary and tertiary wastewater treatment processes can achieve substantial reductions in microbial hazards, including bacteria, enteric viruses and protozoa. The review also notes that available quantitative microbial risk assessments have found that reclaimed water use does not appreciably increase public-health risk from enteric pathogens and , in some situations, may be safer than more traditional irrigation-water sources.
At the same time, the authors identify important areas where more research is needed. These include the effectiveness of treatment processes against more resistant pathogens, particularly Cyclospora cayetanensis, as well as continued evaluation of chemical constituents of emerging concerns, such as pharmaceuticals and industrial chemicals.
The review provides a resource for growers, water providers, regulators, buyers and researchers seeking to better understand the opportunities and considerations associated with reclaimed water use in production. As water challenges continue to evolve, the publication underscores the importance of treatment, monitoring, system management and science-based decision-making in protecting both agricultural water resilience and producing safety.