Why Do I Have Mice in My Apartment? Causes, Entry Points and Fixes
Clean apartments get mice too. In New York City, mice come in because the building has gaps, not because the tenant is messy. This guide explains what attracts them, how they get in, where they hide and what to do in the first week.
What causes mice in apartments
- Entry points: a mouse can squeeze through a gap about the width of a pencil. Pipe openings, cracks at baseboards and gaps around radiators are common.
- Shared walls and pipe chases: mice move between apartments, so a neighbor's problem becomes yours.
- Food and water: crumbs, open pet food and slow leaks keep them nearby.
- Cold weather: as temperatures drop in fall, mice move indoors looking for warmth.
- Construction and renovation: opened walls and disturbed nests send mice into new spaces.
A very clean kitchen helps, but it does not close the gaps.
How mice get into apartments
The most common routes are around pipes under sinks and behind stoves, gaps at the base of cabinets, openings around radiator pipes, vents and utility lines, and damaged door sweeps in hallways and basements. In older buildings with shared basements, mice can travel several floors inside walls.
A technician's inspection follows droppings and grease marks to find these routes, which is why photos and notes about where you see signs help.
Where mice hide
- Behind and under the stove and refrigerator.
- Inside kitchen cabinets and under sinks.
- In wall voids next to pipes.
- Behind radiator covers and in closets with stored paper or fabric.
- In ceilings above drop ceilings and in basements.
Mice are mostly active at night, so hearing scratching in walls or finding droppings in the morning is often the first sign.
What to do in the first week
- Take dated photos of droppings, gnaw marks and any holes.
- Move food into glass or hard plastic and take out trash daily.
- Wipe surfaces and vacuum droppings while wearing gloves, using damp paper towels rather than dry sweeping.
- Set snap traps along walls where you see signs.
- Tell your landlord or managing agent in writing and keep a copy.
- Schedule a professional inspection if signs continue after a week.
Your rights as a tenant
In a NYC rental, the owner is generally responsible for keeping the building free of mice and rats. If the owner does not act after written notice, you can file a 311 complaint so HPD can inspect. Our landlord and tenant guide has the steps and the timelines HPD publishes.
This is general information, not legal advice.
Frequently Asked Questions
Why do I have mice if my apartment is clean?
Mice come in through gaps and shared walls. Cleanliness reduces how long they stay, but it does not block entry points.
How do mice get into apartments?
Through openings around pipes, radiators, cabinets, vents and door gaps. They can fit through very small spaces.
Where do mice hide in an apartment?
Behind stoves and refrigerators, under sinks, inside wall voids, behind radiator covers and in closets.
Are mice common in NYC apartments?
Yes. Dense housing, older buildings and shared walls make mice common across all five boroughs.
What should I do if I see one mouse?
Treat it as a sign of more. Set traps, seal what you can, document it and tell the landlord. Call a professional if signs continue.
Sources
Rules and numbers on this page come from these public sources. Check them for the latest wording, since agencies update their pages.