Landlords and tenants both have certain legal rights when they enter into a lease or rental arrangement. A tenant has the right to live in a habitable environment, therefore a landlord has a responsibility to ensure that the rented property is safe. Laws vary by city and state; some laws protect tenants against mold or rodent infestations, while other laws ensure that fixtures are in proper working order. A residential tenant has the right to privacy in their rented property, though a landlord still has the right to enter a rental property under specific conditions. A landlord has the right to evict a tenant for nonpayment of rent or other lease violations, and similarly a tenant has the right to make a defense against an eviction. A landlord does not have the right to lock a tenant out of their property, and a tenant may sue a landlord for unlawful eviction.