The landlord-tenant relationship is sometimes a complicated one. Some renters take a lot of care and pride in turning an apartment or duplex into their home, but the reality remains that the building belongs to somebody else. So what happens when, in the bitter cold, apartment pipes freeze and possibly even burst? Who's responsible?
The Answer? It Depends.
At the basic level, a rental agreement requires that landlords provide their tenants with housing in a habitable condition, which means a weather proofed dwelling and working plumbing. The tenant has a related obligation (usually in writing, although sometimes it's not explicitly stated in the lease) to use the rented space and all its facilities in a reasonable manner, and to neither deliberately or negligently damage the apartment.
When it comes to damage relating to frozen or burst pipes, renters should always check their lease to determine if there are any applicable agreements with their landlord relating to living in winter conditions. During a particularly cold spell, it could be argued that "reasonable use" of the apartment plumbing includes renters taking precautions against burst pipes, such as letting sink and bathtub faucets drip during extreme cold. Tenants might also be required by the lease to keep the apartment thermostat above a reasonable temperature (such as 60°F) to help prevent weather damage.
Ultimately, if a tenant is reasonably taking care of the apartment but the pipes still end up freezing or bursting, it's the landlord who is on the hook for repairing damage to the property. That does not include, however, damage to renters' personal property within the premises if pipes burst and cause the apartment to flood (just another good reason to have renter's insurance).