New York City is home to millions of mice, primarily house mice that live inside apartment buildings year-round and white-footed mice that enter structures from fall through spring. If you’re searching this, you’re probably dealing with one (or more) in your apartment. Here’s what you need to know about the mice sharing your space, the health risks they carry, and what your landlord is legally required to do about them.
Which Mice Live in NYC Apartments
The most common species inside NYC buildings is the house mouse. Adults are 2.5 to 3.75 inches long with a tail roughly the same length as the body. They have large ears, large eyes, a pointed nose, and uniformly colored grey-brown fur on both their backs and bellies. House mice can live their entire lives indoors, which is why they thrive in apartment buildings regardless of season.
White-footed mice are roughly the same size and shape but have distinctly white fur on their bellies. They spend most of their time outdoors and typically enter buildings between fall and spring looking for warmth. If you spot one inside, it means there’s an opening in your building’s exterior they’re using to get in. In NYC parks, white-footed mice are also the primary carriers of the bacteria that causes Lyme disease, though ticks are the actual transmission vector to humans.
Health Risks From NYC Mice
NYC mice are not just a nuisance. A large-scale genetic analysis by Columbia University’s Center for Infection and Immunity found that city house mice carry several bacteria responsible for gastrointestinal illness in people. Their droppings contained C. difficile, E. coli, Shigella, and Salmonella. Salmonella alone causes 1.4 million cases of food poisoning in the U.S. annually, along with 15,000 hospitalizations and 400 deaths. Some of these bacteria showed genes for resistance to common antibiotics, meaning standard treatments might not work for infections traced back to mouse contamination.
The same study identified 36 viruses in NYC mice, including six previously unknown viruses. None are currently known to infect humans, but researchers found genetic sequences matching viruses that infect dogs, chickens, and pigs, suggesting these viruses had jumped between species before and could potentially do so again.
Rodents in the city also transmit leptospirosis, a bacterial infection spread through contact with infected animal urine. Rats are the most common source in NYC, but mice contribute to the risk. The bacteria can enter your body through your eyes, nose, mouth, or any open wound, and contaminated water, soil, or food can also carry it. The number of people diagnosed with leptospirosis in NYC has been increasing in recent years.
What Your Landlord Is Required to Do
Under NYC housing maintenance code, building owners are legally required to maintain their premises free from pests, including mice. This is not optional and not dependent on your lease terms. If you have mice, your landlord, managing agent, or superintendent is responsible for addressing the problem.
Start by notifying your landlord directly. If they don’t act, you can file a complaint through NYC 311 about mice inside your apartment or in common areas of your building. The Department of Housing Preservation and Development (HPD) will then contact your building’s managing agent and advise them that a violation may be issued if the condition isn’t corrected immediately. If the problem persists, HPD sends a uniformed code enforcement inspector to your apartment. During that inspection, they’ll also check for other violations like non-working smoke detectors, mold, and lead paint.
If your landlord still doesn’t fix the problem after HPD involvement, you can take legal action in Housing Court. Keep records of every communication with your landlord and HPD. Repeatedly failing to address pest complaints can constitute tenant harassment, which is illegal in NYC. Landlords who deliberately neglect reported conditions, including interrupting essential services, can face legal consequences.
How Mice Get In and How to Keep Them Out
A mouse can squeeze through a hole the size of a dime. They follow pipes, wiring, and gaps around radiators and cabinets to move between apartments and floors. In older NYC buildings, the infrastructure practically invites them: cracked walls, gaps around pipes where they enter from the basement, poorly sealed doors, and openings around utility lines.
The NYC Department of Health recommends an approach called integrated pest management, which focuses on fixing the underlying conditions that attract and sustain mice rather than relying solely on traps or poison. The core steps include sealing holes and cracks in walls and floors, storing food in airtight containers, keeping garbage in tightly closed bins, and eliminating water sources like leaky pipes. Steel wool stuffed into small gaps works as a temporary seal since mice can’t chew through it easily, but permanent repairs with caulk, plaster, or metal flashing are more effective long-term.
For your own apartment, focus on what you can control. Store all food, including pet food, in sealed glass or metal containers. Take garbage out nightly rather than letting it sit. Clean crumbs and grease from counters, stovetops, and floors. Check under your sink, around radiator pipes, and behind your stove for gaps, and seal anything you find. Snap traps placed along walls where you’ve seen droppings are more effective than glue traps for most situations.
Building-wide problems require building-wide solutions. If your landlord hires a licensed pest professional and implements an IPM plan, the results tend to be more lasting. IPM reduces reliance on chemical pesticides (which can trigger asthma), prevents structural damage from ongoing infestations, and addresses the root causes rather than just killing individual mice. A single apartment being clean won’t solve the problem if the building has unsealed entry points and shared walls full of gaps.
Signs You Have Mice vs. Rats
Mice leave small, dark droppings about the size of a grain of rice, typically clustered near food sources or along walls. Rat droppings are significantly larger, roughly the size of a raisin. If you’re hearing scratching in the walls at night, mice tend to produce lighter, faster sounds compared to the heavier thumping of rats. Mouse tracks and gnaw marks are also noticeably smaller. Mice chew small, clean-edged holes in food packaging, while rats tear through materials more aggressively.
Knowing which rodent you’re dealing with matters because the approach differs. Mice are curious and will investigate new objects like traps quickly, while rats are cautious and may avoid traps for days. If you’re seeing both large and small droppings, your building likely has both species, which is common in NYC and warrants a professional response rather than DIY efforts alone.