What is a landlord actually required to fix?

Nearly every state recognizes an implied warranty of habitability, meaning a rental must be fit to live in regardless of what the lease says. The core requirements typically include working heat, hot and cold running water, functioning plumbing and sewage disposal, safe electrical systems, structural integrity of floors, walls, and roof, working locks on doors and windows, compliance with building and housing codes, and freedom from significant pest infestation. Landlords generally cannot contract out of these duties, so a lease clause purporting to waive them is usually unenforceable.

What is not required is broader than tenants expect. Cosmetic conditions, dated appliances that function, and amenities not promised in the lease generally fall outside the warranty. Damage caused by the tenant is the tenant's responsibility. Air conditioning is a habitability requirement in some jurisdictions and not others, which is a meaningful difference in hot climates and worth checking locally.

The procedure is what determines whether the right is worth anything. Notify in writing, describe the problem specifically, date it, and keep a copy, since verbal requests are the single most common reason tenants lose these disputes. Allow a reasonable time for repair, which some states define in days for essential services. If the landlord fails to act, remedies vary by state and may include repair and deduct, where you arrange the fix and subtract the cost from rent, rent withholding into an escrow account, reporting to a housing code enforcement agency, or terminating the lease for constructive eviction in severe cases. Follow your state's procedure precisely, because simply stopping rent payment without using the prescribed mechanism can expose you to eviction. Retaliation for exercising these rights, including raising rent or refusing renewal shortly after a complaint, is prohibited in most states and is often presumed if it occurs within a defined window.