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. There was no implied warranty of habitability for tenants at common law and the legal doctrine has since developed in many jurisdictions through housing laws and regulations. Habitability is a common law doctrine that is largely synonymous with tenantability. In order to be habitable, such housing usually: • must provide shelter, with working locks • must be heated in the winter months • must not be infested with vermin, roaches, termites, or mold • requires the landlord to stop other tenants from making too much noise, second-hand smoke, or from selling narcotics • must provide potable water • each jurisdiction may have various rules.