Postal Regulations / Resources

The USPS focuses on providing the best mail delivery solutions

The USPS generally prefers to initiate a centralized form of mail delivery in new developments because it is the best method of providing mail service to its customers. Centralized mail delivery is efficient, cost effective and also the most environmentally sensitive method of delivering mail to the growing number of U.S. households and businesses.

Over the past five years, the USPS has added approximately 1.4 million new mail delivery points each year! At this time, the U.S. Postal Service delivers mail to about 300 million people at more than 148 million locations every day. Centralized mail delivery systems help the USPS manage these deliveries most effectively while minimizing the resources required in providing excellent service. Be sure to check with local postal authorities to learn of local delivery guidelines and requirements which may be required in addition to the new mailbox regulations for new construction.

The Postal Service modified the regulation for new construction due to changing customer mailing habits and specific mail and package volume trends. Postal Service statistics indicate customers receive more mail and of varying sizes than at the time of the last updated standard which prescribed design limitations that are no longer consistent with the operational requirements of the Postal Service.

The new standard (which became mandatory in October 2006) requires mailbox receptacles with increased protection for the mail, benefiting both senders and addressees; improves the overall safety of the equipment in use; reduces maintenance costs incurred by buildings; and results in cleaner lobbies with less clutter. Finally, the newly designed receptacle is easier to access and serve by carriers, thereby helping to reduce Postal Service costs and becoming the “greenest” delivery method.

Centralized mail delivery equipment which fulfills this regulation can be in the form of any "clustered" type mailbox – including free-standing, pedestal-mounted cluster box units (CBU), or other STD-4C mailboxes mounted in a wall or kiosk.

The following documents include important information about Postal Regulations and mailbox design standards:


STD-4C USPS Specification Overview

STD-4C Federal Register Rules and Regulations

STD-4B USPS Standards (superseded by STD-4C)


Canada Post Mailbox Regulations

Canada Post Delivery Planning Standards


USPS Approved Products

The following documents include lists of USPS Approved products and their manufacturers:

Postal Bulletin - May 2013 (full document)

          USPS Approved Mailbox Products 2013-2014(all)

                    USPS Approved Cluster Box Unit Products 2013 - 2014

                    USPS Approved Std-4C Mailbox Products 2013 - 2014

                    USPS Approved Horizontal Mailbox Products 2013-2014

USPS Approved Mail Receptacles List


Postal References

The following documents include additional Postal References for USPS Delivery:

STD-4C Accessibility Guide

STD-4C Quick Reference

STD-4B+ and STD-4C Selection Guide


Postal Locator

The following US Postal Service website will aide in searching for local postal authorities:

USPS Locator