As more households adopt eco-friendly practices, rain barrels have surged in popularity as a sustainable method to conserve water and reduce stormwater runoff. These systems capture rainwater for irrigation, helping homeowners cut down on water bills while supporting the environment.
However, new research from the University of Illinois at Urbana-Champaign reveals a hidden downside: rain barrels can become ideal breeding grounds for mosquitoes if not properly maintained.
Mosquitoes and Rain Barrels: A Public Health Concern
In a study recently published in the Journal of Medical Entomology, researchers surveyed 115 residential rain barrels across 53 households in Champaign County, Illinois, from June to September 2016. The findings were concerning: over 50% of households had at least one mosquito-positive rain barrel.
Mosquitoes are more than just a backyard nuisance—they are vectors of dangerous diseases like West Nile virus, which continues to pose a public health risk. Urban and suburban areas often harbor man-made mosquito habitats, with standing water being essential for mosquito larvae development. Unfortunately, poorly covered or untreated rain barrels provide the perfect environment.
Simple Solutions to Prevent Mosquito Breeding
The research team, led by Dr. Brian Allan, Professor of Entomology at the University of Illinois, evaluated various mosquito prevention techniques used by homeowners. Their analysis showed that rain barrels equipped with mesh lids were significantly less likely to harbor mosquito larvae. Mesh barriers physically block mosquitoes from accessing the water, offering a straightforward, affordable solution.
In addition to mesh covers, other effective mosquito control methods included:
- Bacillus thuringiensis israelensis (Bti): a naturally occurring bacterial larvicide.
- Chlorine treatments: used in small, safe quantities.
- Goldfish or other mosquito predators: biological control agents that feed on larvae.
These treatments are recommended by vector control experts and, when properly applied, dramatically reduce mosquito populations.
Homeowner Awareness Is Key
While many participants were aware of short-term strategies like dumping out standing water, few knew about long-term preventive measures. Educating the public on sustainable mosquito prevention techniques is essential to keep rain barrels safe and effective.
“There are simple, proven ways to reduce mosquito breeding in rain barrels, but they require consistent homeowner action,” said Becky Cloud, the study’s lead author and a graduate student in the Program in Ecology, Evolution & Conservation Biology at the University of Illinois.
Education and Outreach: The Next Step
Community outreach programs by universities, public health departments, and mosquito abatement districts are crucial. By offering training and resources, these organizations can help homeowners take proactive steps to mosquito-proof their rain barrels.
Making Rain Barrels Safe and Sustainable
With proper maintenance and awareness, rain barrels can remain a valuable green infrastructure tool for sustainable water management. Preventing mosquito infestations ensures they benefit the environment without putting public health at risk.
Study Reference:
Cloud, R. E., Allan, B. F., Mackay, A., Sanchez, M., & Wangen, C. (2025). Evaluating vector mosquito occurrence in residential rain barrels in central Illinois. Journal of Medical Entomology. DOI: 10.1093/jme/tjaf019
Learn more at iSEE’s Stormwater and Mosquito Control Project.