Unfortunately, this article is far too short to do justice to this important topic. In a nutshell, a landlord's duty to repair arises from both the law and from the terms of the lease. Landlord-tenant law is generally governed by state and local law, and states and localities differ quite significantly concerning the landlord's legal duty to repair rental premises. The general long-term trend has been to hold the landlord responsible for more repair duties than was previously the case and at the same time allow the landlord and tenant wide lattitude for contractually altering these statutory repair duties. Nevertheless, the first place you want to look to determine who has the obligation to fix what is your lease contract.

Some of the landlord's duties to repair rental premises are owed to the local and state governments rather than to the tenant (complying with the fire code, for example). Thus when the landlord fails to repair a fire code violation, the tenant may have no legal recourse against him and would be faced with a choice between repairing the condition at his own expense or reporting the landlord to the authorities (and thus risk having the premises condemned by the government if the violation is serious enough). That is why some jurisdictions have enacted "special habitability statutes" allowing tenants to make repairs at their own expense and then deduct the cost from their rent.

If the landlord fails to repair in violation of the terms of the lease, in most jurisdictions the tenant need not resort to suing the landlord - he may pay for the repairs himself and deduct the expense from his rent. He may even be required to make repairs as soon as possible in order to prevent the condition from getting worse (in this case, any extra repair expenses caused by the tenant ignoring the condition may not be deductible from rent unless the landlord knew about the condition too).

What if the failure to repair occurs in common areas? For example, what if the landlord owns the entire building but does not keep the hallways and stairways in good repair? In this case, most jurisdictions do not allow the tenant to repair the condition himself and deduct the cost from his rent - but if he falls down the stairs because the landlord didn't replace a burnt-out light bulb, the tenant can still sue the landlord for damages.