USPS Regulations

Commercial Mailbox Guidelines for New Construction and Replacement

Guidelines for Upgrading or Replacing Your Commercial Mailboxes

Americans with Disabilities Act (ADA) Information

ADA Compliance Guidelines-for 4C Horizontal Mailboxes

United States Postal Service Information

For new construction and replacement information of existing equipment

USPS National Delivery Planning Standards (PDF) 

– includes 1 parcel locker to every 5 mailbox compartments requirement (1:5 ratio) – see page 13 (effective July 2020)

 USPS Mailbox Height Regulations for Installing Commercial Mailboxes

Commercial mailboxes for U.S.P.S. delivery include Cluster Box Units (CBU’s), 4C Horizontal Mailboxes, 4B+ Horizontal Mailboxes and 4B+ Vertical Mailboxes. These products are commonly used in apartment complexes, commercial buildings, residential developments, condominiums and several other applications.

4C Horizontal Mailboxes must be installed according to postal regulations including the mailbox height requirements listed below:

• 67”- The tenant lock in the highest mailbox shall be no more than 67” above the finished floor.

• 48”- The USPS Arrow lock (master door lock) opening shall be no more than 48” above the finish floor. In compliance with ADA regulations, the high forward and high side reach shall be a maximum of 48” above the finished floor.

• 36”- The USPS Arrow lock (master door lock) opening shall be a minimum of 36” above the finished floor.

• 28”- The floor of the lowest tenant mailbox shall be no less than 28” above the finished floor.

• 15”- The floor of the lowest parcel locker shall be no less than 15” above the finished floor. In compliance with ADA regulations, the low forward and low side reach shall be a minimum of 15” above the finished floor.