Apartment rental agreements are legally binding contracts, which means you can sign away some rights. Every state has its own laws addressing relationships between landlords and their tenants, so some provisions may be illegal in one state and legal in another and leases can't force you to break the law. However, a breach of any lease can render it invalid.

Broken Vows

Leases are most frequently invalidated when one party breaches the agreement. For example, if your apartment isn't ready on the move-in date or your landlord gives you an apartment that's substantially different than the one you were promised, your lease isn't valid. If you break your lease after moving in by violating pet rules, missing rent payments or damaging the property, the landlord could move to evict you, voiding the lease.

Illegal Acts

No contract can require either party to do something illegal, though your landlord can ask you to give up certain rights as part of the lease. She could, for example, make you give up your right to have pets. She couldn't, however, refuse to lease to you based on your race or ethnicity, or offer rental contracts only to tenants willing to engage in illegal activities such as selling drugs.

Landlord-Tenant Laws

Your leasing agreement can't violate your state's landlord-tenant laws. Every state establishes specific procedures a landlord must follow to evict a tenant. If your landlord requires that you move out immediately if you violate your lease, this may contradict landlord-tenant laws in your state and is therefore illegal. Similarly, your landlord can't require that you forfeit your security deposit if you don't damage the apartment.

Insufficient Information

A lease agreement has to contain enough information for each party to understand its terms. Again, state requirements vary, but your lease generally has to include the apartment address, the amount of rent, the length of the lease and any property-specific terms such as pet prohibitions. If your lease doesn't contain this minimum information, a court may rule it invalid.