Garbage = RATS
It's what researchers find when they go into Chicago's alleys and count.
Loose garbage was the No. 1 predictor of how many rats were found in Chicago alleys, and how many rat complaints.
Murray et al., 2018 · Chicago
Alleys with more garbage lying around trapped 2.3× the rats.
Himsworth et al., 2014 · Vancouver
A city rat usually lives within about 1 block of where it eats.
A dumpster that overflows feeds the rats on its own block.
Byers et al., 2019 · systematic review
Chicago writes just 1.2% of its rat-harborage tickets on a Saturday or Sunday.
Let's change that.
Dept. of Streets and Sanitation records, 2026
Chicago has already studied this
In 2018, researchers at Lincoln Park Zoo's Urban Wildlife Institute trapped rats in 52 alleys in 13 Chicago neighborhoods and scored how much loose garbage each one had. Alleys with more loose garbage had more rats and more rat complaints. In the authors' words, uncontained garbage was "the best predictor of both complaints and rat abundance."
A follow-up study in 2021 looked at seven years of 311 records, tract by tract, across the whole city. Neighborhoods with more complaints about garbage in the alley, dumpsters not emptied, and overflowing carts also had more rat complaints. The authors recommended "securing food waste from residential and commercial sources."
In Chicago, rat complaints rise and fall with the number of rats actually trapped - so 311 data is a useful way to see where the rats are.
Take the food away, and the rats go
When COVID closed the University of California, Santa Cruz in 2020, the dining-hall garbage stopped overnight. Researchers had cameras out, and rat activity dropped sharply. The native mice and other small animals that share the same ground didn't change.
The same thing happened in New York in reverse. When restaurants closed, rats went looking for the food that had stopped, and 311 rat calls clustered around the shuttered restaurants.
Rats eat close to home
A city rat typically ranges 30 to 45 meters, and genetic studies put most rats within about a block of where they were born. Where food is easy, they barely travel at all.
That's why we think the building should pay. A container that overflows every weekend isn't feeding "the city's rats." It's feeding the rats in that alley, the ones that get into the neighbors' garages and yards.
Why weekends
Chicago doesn't collect garbage from businesses or from buildings with five or more units. Those owners hire a private hauler, and the City Code only requires a pickup "at least once each week." The common twice-a-week schedules are Monday and Thursday, or Tuesday and Friday. Either way, the longest stretch between pickups, four days, runs over Saturday and Sunday.
Those are the days the City almost never writes a ticket.
The research
- Murray, M. H., et al. (2018). Public complaints reflect rat relative abundance across diverse urban neighborhoods. Frontiers in Ecology and Evolution, 6, 189. The Chicago alley study.
- Sánchez, C. A., Rios, M. J., & Murray, M. H. (2021). Social and environmental correlates of rat complaints in Chicago. Journal of Urban Ecology, 7(1). The citywide 311 study.
- Himsworth, C. G., et al. (2014). A mixed methods approach to exploring the relationship between Norway rat abundance and features of the urban environment in an inner-city neighborhood of Vancouver, Canada. PLoS ONE, 9(5), e97776.
- Shukla, I., & Wilmers, C. C. (2024). Waste reduction decreases rat activity from peri-urban environment. PLoS ONE, 19(11), e0308917. The Santa Cruz study.
- Parsons, M. H., et al. (2021). Rats and the COVID-19 pandemic: early data on the global emergence of rats in response to social distancing. Journal of Urban Ecology, 7(1). The New York restaurants study.
- Byers, K. A., Lee, M. J., Patrick, D. M., & Himsworth, C. G. (2019). Rats about town: a systematic review of rat movement in urban ecosystems. Frontiers in Ecology and Evolution, 7, 13.