A more thorough explanation:

In landlord-tenant law, a three-day notice is a notice given to tenants who have not paid their rent. The notice demands that the tenant either pay the rent owed or leave the property. Proper service is required when issuing a three-day notice, and different jurisdictions have different guidelines for what constitutes proper service.

In California, a three-day notice can be delivered in three ways:

1. By delivering a copy to the tenant personally
2. If the tenant is not at home or work, by leaving a copy with someone of suitable age and discretion at either place and sending a copy through the mail to the tenant's residence
3. If the tenant's residence and business cannot be found, by affixing a copy in a conspicuous place on the property and delivering a copy to a person residing there, as well as sending a copy through the mail to the tenant at the property

Mailing a three-day notice to the tenant alone is not enough and will make the notice unenforceable.

A three-day notice is usually the first step in a detainer action. In some states, like California, Ohio, and Texas, a valid three-day notice is required before a landlord can file a forcible entry and detainer suit. However, if the notice does not meet the service or information requirements, it is invalid and cannot support a landlord's claim for possession.

It is important to note that a three-day notice does not necessarily eliminate a tenant's obligation to pay rent for the rest of the lease term. In Ohio, for example, a tenant may still be liable for rent until the landlord finds a new tenant. However, if the landlord accepts future rental payments, a previously issued three-day notice is automatically waived, and any subsequent action for possession based on that notice is also waived.