Rats are on the ballot in Canadian municipal elections this fall, with several political parties promising to tackle city rat problems. While rats may seem like a niche election issue, they can point to broader societal concerns about housing, public services and civic engagement. Rats are ubiquitous urban residents that cities have attempted to evict for centuries. Often portrayed as dirty pests and bringers of plague, they can harbour pathogens that cause illnesses to people and pets, like rat bite fever and leptospirosis. So why have cities had so little success in reducing rat numbers? Well, rats are synanthropes, species that benefit from living alongside humans, and have adapted remarkably well to our paved, cacophonic and bustling streets. Cities provide abundant resources for rats to thrive: food scraps are meals; standing water on sidewalks supplies drinking water; and cracks in buildings offer access to shelter. Municipal policies and bylaws shape how these environments are built and maintained, influencing living conditions for both people and rats. Thinking about rats through municipal elections can offer a more tangible way to understand how complex it is to manage rats without addressing broader issues. We reviewed studies from high-income country cities. Using synthesis and complex systems mapping methods, we examined the social and environmental conditions linked to urban rats, how they influence where people encounter rats across different neighbourhoods and how they impact residents’ ability to respond. Here are a few of our findings and how they connect to municipal issues, using examples from Vancouver’s upcoming election.Habitability, affordability and securityOur homes are the most intimate spaces where we can encounter rats. Adequate housing is a human right enshrined under many nations’ laws, including Canada’s. Housing habitability, affordability and security — components of adequate housing — can impact encounters between residents and rats. Concerns about “living in housing that doesn’t meet [people’s] needs” refers to habitability — or the quality of housing that guarantees safety and protection against threats to health. Cracks and gaps in older, poorly maintained dwellings allow rats into places where people eat and sleep. Infestations can contaminate food and are linked to anxiety, depressive symptoms and worries about health. Household rat allergen exposure is associated with increased asthma-related health-care issues, including among children. Affordability matters, too. When housing costs leave little money for other essentials due to people “paying more than they can afford,” residents may be unable to pay for measures to prevent or remediate rat infestations, adding financial strain to households already facing competing needs. Housing insecurity is also central to why some residents might be more impacted by rats than others. For example, renters may be more likely to experience sustained rat infestations. Fear of eviction or landlord-tenant conflicts can discourage renters from seeking help. Landlord inaction can leave tenants living with persistent infestations and little power to act. Commitments to strengthen tenant protections could reduce barriers in resolving these problems by holding landlords to the city’s maintenance standards. This bylaw requires owners to eliminate pest infestations and maintain their properties to prevent pest harbourage.Unhoused populations may be at higher risk of rat contact. In Vancouver, the number of unhoused people increased 12 per cent between 2023 and 2025, a general trend mirrored across CanadaProlonged periods outdoors, alongside limited sanitation access, can also increase contact with rats. This speaks to candidate concerns that “in a wealthy city like Vancouver, people are sleeping rough.” Yet city councils have some power over housing supply. Municipalities play an important role in land use policy and regulations, which matter for reducing rodent exposures through availability of safe, stable housing. Waste, sanitation, neighbourhood conditionsCities are hubs for consumption and waste like trash, food scraps, and sewage. Missed garbage pickups and dirty streets are more than a nuisance, they’re also culprits of ratty conditions.Previous studies have linked rat problems with dog waste and human waste. These findings connect to candidate criticisms like “city streets and parks are covered with animal and human poop.” In fact, open defecation is an ongoing urban issue related to housing insecurity and limited public washrooms.But, when it comes to waste and rats, not all neighbourhoods are the same. Conditions and resources that support rats and residents’ ability to address them vary across neighbourhoods, with infestations often occurring in neighbourhoods experiencing long-term disinvestment and structural marginalization. Civic engagementSo how do municipalities know where to target interventions? Many cities use municipal 311 services to understand how rats are distributed across neighbourhoods. They also capture resident concerns to draw municipal attention to problems affecting everyday life. When it comes to rat management, 311 aligns with pledges for “a City Hall that listens” and seeks “involvement of local residents.” However, rat studies acknowledge the limitations of these data in their current form: residents differ in access, ability, knowledge and trust to report to 311 systems. So, while 311 services can be channels for civic participation and a pragmatic way to monitor and manage rats, they can also reflect broader social inequities.Beyond the electionsThe real work is done after voting day comes and goes. Luckily, Vancouver, like numerous other cities, already has a Healthy City Strategy that aligns with proactive and equitable rat management. This approach prioritizes determinants of health — including housing, sanitation and access to protective resources — by addressing root causes and directing resources to where barriers are greater. For rat management, this means identifying where infestations and conditions that sustain them coincide with limited resident resources to respond.So, the next time you see a rat scurrying along, perhaps you’ll think about what rats symbolize — not just dirt and disease, but our everyday urban living.Christine Yanagawa received funding from the Natural Sciences and Engineering Research Council of Canada; the Tri-Agency-funded SMART Healthy Cities Training Platform; and the Canadian Institutes of Health Research-funded Canadian One Health Training Program on Emerging Zoonoses.Kaylee Byers is co-lead of the Vancouver Rat Project and collaborates with the Chicago Rat Project. She receives funding from Michael Smith Health Research BC (Scholar Award). She holds a Natural Sciences and Engineering Research Council of Canada Discovery Horizons Grant and MITACS Accelerate funding for research on urban rats.