A three-day notice is a notice that the landlord is going to provide to the tenant when the tenant has failed to pay the rent. What it does is it gives the opportunity to the tenant to pay the rent within three days. Now, that three days does not include the day of service, weekends or holidays. The landlord will want to provide that notice to the tenant giving that tenant an opportunity within those three days to pay the rent before the landlord can start the eviction process.