Urban agriculture is growing quickly across the U.S. to address food insecurity and climate change, yet it is limited by irrigation water costs and availability of high-quality water. Rainwater harvesting could provide reliable, high-quality water for urban farms, yet there is currently low adoption because of water quality concerns and uncertainty about costs and benefits.

Harvested rainwater typically meets food safety standards but may require further treatment. Zero valent iron (ZVI) sand filters can significantly reduce the concentration of fecal indicator bacteria (ex. E. coli and total coliforms) as well as foodborne pathogens (ex. Salmonella) in water. Despite these prior results, the lack of on-farm validation studies and comprehensive cost-benefit analyses have impeded widespread rainwater harvesting adoption in urban agriculture. There is an immediate need to increase rainwater harvesting in urban agriculture to produce safe and nutritious foods for underserved communities and address climate change’s stress on water sources.

To address these critical challenges and in response to the Critical Agricultural Research and Extension (CARE) program, we propose an integrated research and Extension project to: 1) field-test an integrated rainwater harvesting, ZVI sand filtration, and irrigation system and confirm water quality and produce safety; 2) evaluate environmental, social, and economic costs and benefits of rainwater harvesting for produce irrigation in underserved urban communities; and 3) develop innovative Extension programming on rainwater harvesting design, quality, and benefits. Our project could provide needed information to urban farmers and policymakers about rainwater harvesting quality and benefits and improve our nation’s agricultural and food systems.