Implied warranty of habitability
The legal rule in most U.S. states that a landlord must keep a rental fit to live in — heat, hot water, working plumbing, and safe, code-compliant systems — regardless of what the lease says.
The implied warranty of habitability is a tenant protection recognized in most U.S. states: by renting out a home, the landlord promises it's safe and livable, and that promise generally can't be waived away in the lease. It's breached when essential services fail — no heat, no hot water, no running water, a non-working toilet, a missing smoke alarm, or other code/safety violations — and the landlord doesn't fix them after written notice. Remedies vary by state and can include the right to repair-and-deduct, withhold rent, or break the lease ([constructive eviction](/glossary/constructive-eviction)). It's the legal backbone of the renter rule of thumb that anything affecting health, safety, or a working essential system is the landlord's job — see [home maintenance for renters](/guides/home-maintenance-for-renters-and-tenants). Exact rights differ by state, so check your local tenant law.