A plan to reduce the rat population in Somerville

by Jessica M. Smith, PhD

What’s the rat problem?

Rats are a fact of city life, but the rat problem in certain parts of Somerville has grown substantially over the last decade. Large scale construction projects, including Assembly Row, the Green Line Extension, and various other large commercial and residential developments displaced rats who then made their homes in the surrounding residential neighborhoods. The problem was exacerbated by changing patterns of food waste and traffic during the COVID-19 pandemic. Rodents are disease vectors, and as such the control of rat populations must be a priority for the public health of the community. Plus, they’re also really creepy. Reader, the author of this paper is frankly quite afraid of rats: they’re scary and gross!

The City of Somerville claims to take the rat problem seriously, but it doesn’t take much investigation to determine that the city isn’t doing much at all. The sole full time employee tasked with addressing the rat problem resigned months ago and has not been replaced. Guidelines for dealing with rats seem out of touch with the realities of living in Somerville, as in this city brochure which encourages residents to bring trash barrels to the curb immediately before trash pick up. I don’t know that any of the many multi-family apartment buildings in Somerville have dedicated trash rooms, so this suggestion is unlikely to be effective.

How can we decrease the rat population?

A critical first step is to invest in an expert rodent-control team that has the resources they need to do their job. This was tried once before - Mayor Curtatone announced his Rodent Action Team in 2014. That team distributed uniform, sturdy trash receptacles to try to reduce the available food sources for rats. They also piloted a non-lethal rat birth control program, though it’s unclear why that program was not expanded. The other recommendations in this paper would be useless or even counterproductive if the city doesn't commit to funding the full-time employees required for a project of this scale.

Effective strategies to control rat population without harming people or wildlife include rodent birth control, or a non-toxic rat-targeted bait such as RatX. Limiting rats’ food supply is also crucial to controlling their population. In cities, this usually means household and restaurant food waste. Somerville previously subsidized rodent-proof home composing tumblers, though that program appears to be on hold. Better than home composting is municipal compost. I, personally, have used Garbage to Garden for years, considerably reducing the amount of rodent food in my trash. A service like this should be available to everyone, free of charge. Another tactic to reduce the abundance of food waste available to rodents is to increase the frequency of garbage pick up in the most affected areas, as well as increasing the frequency of trash pick up in public garbage cans. Open-top public trash cans should also be replaced with a rat-proof trash receptacle, ideally one that is accessible to folks with disabilities or who use mobility aids.

A comprehensive program for rat control needs to include cooperation from all (or, realistically, a substantial fraction of) residents of Somerville. A large scale public education campaign will be required, but so will allowing renters to participate in city rat-mitigation programs. Before April 2021, only owner-occupied properties were eligible for the Residential Rodent Control Assistance Program. In a city with a majority of residents renting their home, the recent expansion to renters is long overdue. Removing barriers such as the liability waiver that homeowners and landlords are currently required to sign, will be critical to engaging residents in municipal rat control programs.

Monitoring the number of rats by population survey is central to evaluate the success of various measures as they’re implemented. We can build a GIS-powered Rat Map as outlined in this document by the CDC so that rodent-control workers can keep up with the size and geographic distribution of the rat population in near real time. We can also measure our success by a decrease in the number of 311 calls the city receives about rats. Visual indicators, like a decrease in droppings or indications of ground routes, can also be a clue to rodent experts that a population is decreasing.

How do we pay for it?

During the term of the next Somerville City Council, the city is poised to receive roughly $90M in COVID relief aid as well as $30M from the Green Line Extension. Since GLX construction and the conditions of the pandemic contributed to the growth in the rat population, the city should use this money to fund a substantial upfront anti-rodent program. To find recurring funds for this program, we can reallocate some excess money from the Somerville Police budget. Real estate developers are required to include a mitigation strategy for displaced rodents during the permitting process. We must regularly inspect construction sites, just as we do for restaurants, to ensure that the city government isn’t footing the bill for a rat problem caused by private developers. Similarly, negotiations for large projects like the GLX and Assembly Row must include pest control plans. The true cost of construction projects includes dealing with the displaced rodents.

Reducing the rat population in Somerville will require substantial investment by the city government. It will also require  cooperation from Somerville residents - an effective rodent control program requires a high degree of local familiarity. No matter how high a wall your garden has, a wily rodent can burrow underneath; your neighbor’s rat problem is your rat problem. We’re all in this together.


About the author: Jess a scientist and Somerville resident who got interested in learning more about rodent control after talking to many Ward 1 & 4 residents who were concerned about the growing rat population. If you have any thoughts on rodent control, please send us an email at hello@charlotteforsomerville.com.

Further reading