Setting up U.S. Postal Service Cluster Box Units

​Because of significant growth taking place in many parts of South Carolina, the U.S. Postal Service is working with builders, developers, municipalities and counties to coordinate the most efficient, cost-effective type of delivery for customers.

The USPS considers many factors when determining the type of mail service to provide to an area, including customer convenience, aesthetics and efficiency. Because central delivery is the most cost-effective method, the USPS prefers to use it whenever appropriate. The USPS determines the type of delivery to be provided before many residents move into a development, so it consults with the developer rather than prospective residents before making the decision.

The USPS has discretion to establish a service known as Cluster Box Units in new areas. It decides to install CBUs after determining that this type of delivery is the most efficient in the specific situation.  

CBUs also provide unique advantages to postal customers, including:

  • Protection of both incoming and outgoing mail from theft – CBUs are locked and vandal-resistant.
  • Potential reduction of home burglaries – the unit shows no buildup of mail as do other types of boxes.
  • Centralized delivery sites equipped with a customer mail collection slot.
  • Decreased fuel consumption, improved air quality and reduced traffic congestion.
  • Decreased costs for developers and homeowners.
  • Increased sense of community for homeowners and sense that the mailbox is a protected, monitored territory.
  • Reduction of dog bites for letter carriers.
  • Improved neighborhood appearance.

The USPS encourages local governments to include a brief statement of the portion of the Postal Operational Manual covering centralized delivery in subdivision regulations. For additional information, contact Wayne McCall at