Can Rats Travel Between Connected Houses?

The University of Nebraska Extension documents rodents crawling along pipes and electrical conduit and gnawing through a wide range of building materials — the same behavior that lets them move through shared-wall cavities and utility chases connecting attached homes. A rat needs only about a ½-inch gap to pass, so any unsealed penetration where plumbing, wiring, or ductwork crosses a shared wall is a usable route between structures.

Peer-reviewed work on shared-wall multi-family dwellings found rodent infestations cluster significantly in units connected by a common wall, floor, or ceiling — direct evidence that the animals are moving through those shared structural elements rather than each unit developing a problem independently. Attached houses follow the same physical logic as apartment buildings, just at a smaller scale.

A rat's normal foraging range of about 150 feet, extending up to a mile under stress, easily spans an entire attached structure, so a colony established on one side has no trouble reaching the other. Trapping and sealing only your unit can clear the rats currently inside it, but if the connected home stays infested and shares even one unsealed penetration, rats re-enter on an ongoing basis.

Coordinate with the connected homeowner or neighbor: trap simultaneously on both sides, and seal shared-wall and utility penetrations from whichever side gives better access. In rental or condo-association situations, this is often a matter for the HOA or property manager to organize, since one owner typically can't seal a shared wall unilaterally.