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What are the requirements for multi-unit mailboxes?

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The USPS requirements for multi-family mailboxes are mainly the same as those for standard residential mailboxes. All mailboxes must meet the following requirements for the USPS to deliver. To ensure that your mailboxes receive USPS delivery, purchase USPS-approved models, which were manufactured with the correct requirements in mind. You’ll also need to keep these rules in mind when you install your multi-family mailboxes:

  • Placement. All residential mailboxes must be 6 to 8 inches away from the curb. They must also be on the right-hand side of the road to enable the mail carrier to deliver.
  • Height. According to regulations, all residential mailboxes, including multi-family units, must have a mail flap between 41 and 45 inches from the ground.
  • Posts. All curbside mailboxes must be mounted with posts no larger than 4 by 4 inches. Steel and aluminum posts that are 2 by 2 are also allowed. Posts can’t be mounted deeper than 2 feet into the ground or shallower than 1 foot.
  • Layout. If a newspaper compartment is included, it cannot touch the mailbox directly. It also cannot be supported by the mailbox itself.
  • Address. The mailbox’s address must be visible, with each letter and number being at least an inch tall. The address must be on the front door or on the flag side of the mailbox.

Locking mailboxes have some additional requirements that must be met:

  • Hopper Flaps. These flaps must turn inwards when mail is delivered and require no extra effort for the postal employee.
  • Slots. Delivery slots must be at least 1.75 inches high and 10 inches side. This allows delivery of priority mail without folding.
  • Size. Locking mailboxes must be large enough to hold a normal volume of mail.

Regardless of what type of mailbox you choose, be sure to check with your postmaster with any questions, or contact us.