Killing rats and keeping them from breeding aren’t keeping the pests at bay, so Cambridge will likely expand composting pickup next year, officials said Monday.
“There’s only so much we can do to ultimately control our rodent population through attacking it. A lot of it is really just about supply of food,” city manager Yi-An Huang told city councillors. He said even the Smart Boxes that electrocute rats, which can cost $300 each per month, are more useful at showing where nests are concentrated than as actual population control, making education and prevention more important.
In addition to the Smart Boxes, over the last three years, the city added 200 more sealed Big Belly trash compactors to replace wrought-iron, open-topped trash receptacles, fixed or maintained 286 older Big Belly models and provided 23,000 trash carts to homes for free. These have helped in rat control efforts, according to a report from Public Works and the Public Health Department.
But rats remain an urgent problem for some. Councillors pointed to a couple of specific buildings where the situation has been dire, including in Harvard Square on University Road, where the problem has reportedly forced tenants out. “They can’t get any relief no matter what people do. They close the holes. They bait,” mayor E. Denise Simmons said. “Families and their children are being terrorized.”
Part of the problem is that although the city’s residential composting program collects nine tons of food waste a day, “we probably still have 30 percent food scraps in our trash itself and our recycling,” said John Nardone, the city’s Public Works commissioner. “We need to get better.”
Nardone and other staff expect to bring recommendations to the council early in 2026 to make food waste pickup mandatory for some larger buildings and commercial establishments, he said. The expansion of the city’s Zero Waste Master Plan was signaled March 25 at a Health and Environment Committee meeting.
University Road improving
The problem on University Road has abated with better trash management and as residents have learned not to leave doors to the outside open, said Dave Power, the city’s so-called rat czar, and now their homes seem to be free of rats even if “there is still some activity around the building.” (No rats could be detected in a walk around the site late Monday, despite a number of trash and recycling bins being out.)
When a nest is found, city staff will “from time to time” pump in carbon monoxide or carbon dioxide to kill rats peacefully, Power said.
Simmons asked for a report back on the University Road property in a month.
A multi-pronged effort
Other efforts continue. The Smart Boxes are “showing very good numbers,” Power said, having zapped 1,149 rats so far this year, up from 377 in their first year of implementation, according to the report. But Smart Box maker Anticimex’s Smart Pipes product, aimed at killing rats in sewers, have disappointed: After 1,381 kills in 2023, there were only 355 last year and 311 so far this year.
“They faced some challenges with the technology,” and the city will probably quit the underground approach and put its money into the aboveground Smart Boxes instead, Power said.
Staff are responding faster to public complaints coming to ISD and the SeeClickFix service, and have cleared 74 percent of properties taking part in the city’s rodent control services since 2021, according to the report. The services, which are free for up to 60 days at housing with four or fewer units, saw a spike in 2022 to 550 applications and since have moderated to an average 254 a year.
“We’re starting in the right direction,” Power said. “People just need to let us know when there’s a problem in their area.”
More Big Belly trash models are on the way, with an eye toward eliminating all of the city’s open-topped trash receptacles.
Rat infertility drugs fail to deliver
Meanwhile, a yearlong pilot of slipping infertility drugs into the food supply of Cambridge and Somerville rats is “not looking very impressive,” said Sam Lipson, the city’s director of environmental health. The cities chose more or less matching sites for the test, including at their public high schools and residential areas – in Cambridge, the Hoyt Field neighborhood in Riverside. To test a commercial area with a lot of restaurants and food scraps that draw the rodents, Cambridge “deliberately picked a really tough location” for the fifth part of the test: Harvard Square.
Health experts suspected a test in an urban area with so many uncontrolled variables might not succeed, because it’s easy for rats to move around. “Rats from one area will move into an adjacent area if opportunity exists,” Lipson said. He full results will be known in March or April, at which time the city will decide whether to continue the program.
This post was updated Nov. 26, 2025, to attribute a quote to Dave Power.
A stronger
Please consider making a financial contribution to maintain, expand and improve Cambridge Day.
We are now a 501(c)3 nonprofit and all donations are tax deductible.
Please consider a recurring contribution.
“When a nest is found, city staff will “from time to time” pump in carbon monoxide or carbon dioxide to kill rats peacefully, Power said.”
Interesting. We use the carbon dioxide trick with dry ice every time a burrow shows up on our property. It works so much better than poison did but it only works if we do it every single day until the burrow stops re-opening not “from time to time.”
We came back from a 2 week vacation to discover the rats had moved into our backyard. There were 2 major burrows. It took a full week of dry ice application but at the end of the week the rats were gone.
I highly recommend dry ice to anyone who has burrows in their yard. Once the burrows stop re-opening, continue to monitor your yard daily. It really works.