Habitability is the conformance of a residence or abode to the implied warranty of habitability. A residence that complies is said to be "habitable". It is an implied warranty or contract, meaning it does not have to be an express contract, covenant, or provision of a contract. It is a common law right of a tenant or legal doctrine.
must be heated in the winter months (typically between October 1 and May 31 in the Northeastern United States)
must not be infested with vermin, such as mice, roaches, termites, mold, etc.
requires the landlord to stop other tenants from making too much noise (as measured by the decibel scale), second-hand smoke, or from selling narcotics
must provide potable water
each jurisdiction may have various rules.
New York law
Some states, such as New York, have given additional statutory protections in addition to those created by caselaw. These statutes include:
Lobby attendant service by a concierge or landlord
Elevator mirrors
Smoke detectors
Window guards
Intercoms and self-locking doors
Protection from lead paint
Consequences
Violation of the warranty of habitability results in constructive eviction, whereby the landlord or lessor has, in effect, evicted the tenant or lessee. The tenant may remedy the problem, or complain to local government authorities for remedies.