USPS Mailbox Requirements

The United States Postal Service has specific requirements for all residential curbside mail boxes. The USPS Domestic Mail Manual sets forth regulations and rules concerning residential curbside mailboxes. The manual describes the standards for letterboxes and other mail receptacles for the deposit or receipt of mail.

Residential Mailboxes

A residential mailbox is any curbside or wall-mounted receptacle which is used for the purpose of receiving material in which postage is paid.

Who Can Use A Mailbox

Only authorized letter carriers may place mail or packages into the mail receptacle. No part of the mail receptacle may be used to deliver anything that does not contain postage. This includes items attached to the box, hung from the box or inserted into the mail box. Any mailable material not displaying postage and found in the mailbox is subject to the same amount of postage as if it were carried by a mail carrier.

Exclusions from USPS Rules

Door slots and other non-lockable bins used with apartment mailboxes are subject to the same regulations as a curbside mailbox. Just keep in mind that a mail slot should be large enough to accommodate the type of mail the homeowner receives. If the mail slot is not large enough, then the mail carrier will cease delivering mail to the residence.

Curbside Mailboxes

All homeowners must keep the area around their mailboxes clear of anything than will obstruct the safe delivery of mail. If the United States Postal Service employee cannot safely reach in and deliver the mail, the postmaster may withdraw delivery to that mailbox.

Any curbside mailbox which is to be installed at the edge of the roadway or curbside of the street and allows it to be served by a mail carrier from a vehicle on any city route, rural route or highway must be approved by the United States Postal Service.

Every curbside mailbox should display the homeowner’s name and address assigned by the local authorities on the flag side of the mailbox. The numbers and letters must be at least one inch high and in a contrasting color in neat, legible letters. If the boxes are grouped and the address cannot be placed on the flag side of the mailbox, then the house number should be inscribed on the door. No advertising of any kind can be placed on the mailbox or the mailbox post.

Mailbox Sizes

There are regulations regarding curbside mailboxes. A curbside mailbox can be one of three size for residential mail: small T1 (C1) size is approximately 5 inches wide by 6 inches tall and 18 ½ inches long, Medium T2 (C2) size is approximately 6 inches wide by 7 inches tall by 19 inches long, and the Large T3 (C3) size is approximately 8 inches wide by 11 ½ inches tall by 22 ½ inches long. The “T” stands for Traditional and the “C” stands for Contemporary. The dimensions reflect the minimum interior size.

Lockable Mailboxes

A locking curbside mail box will help to deter most thieves from stealing your mail. Many residential mailboxes are available with a built-in locking mechanism. If your mailbox is not equipped with a lock, you can purchase one from several online sources. Locks are essential for deterring thieves and are extremely important when the homeowner is away for several days and unable to retrieve the mail. Also note that the U.S. Postal Service will not open locked boxes nor will they accept a key for that purpose. Locks can be installed on both post and wall mounted mailboxes. When installing a lock on an existing mailbox, make sure your mailbox is strong enough to withstand an attack. Lockable mailboxes should be large enough so that if the homeowner is away for several days, it can accommodate the overflow of mail.

Novelty Mailboxes

Novelty mailboxes are mailboxes that have been dressed up or decorated in some fashion. The same rules and regulations apply to novelty mailboxes as do pre-approved and custom-built mailboxes.

Where to Place A Residential Curbside Mailbox

All curbside mailboxes must be placed in a safe and convenient place. The box must be on the right-hand side of the road in the direction of travel of the mail carrier’s normal route. The box should not be placed where it places the mail carrier in a dangerous situation or drive on the incorrect side of the road or violate any traffic laws.

The curbside mailbox post should be positioned 6-8 inches from the curb and approximately 42-46 inches high measured from the lawn to the top of the installed curbside mailbox, not the top of the post. If the post has a vertical arm, the arm should not extend any closer than 6 inches from the curb. When installing your new set, make sure your set complies with these regulations.

Wall Mount Mailboxes

The USPS does not have rules or regulations for wall mount mailboxes, however, you should notify your local mail carrier before installation to ensure proper placement of the mailbox and check for any local codes or regulations governing placement of the mailbox. The product should operate easily and nothing should obstruct the opening and closing of the lid. Also check with your home owners association to see if they have any rules or requirements which you need to comply with.

Building Your Own Mailbox

All custom built curbside mailboxes must meet the same standards as approved mailboxes. Custom built mailboxes should have a flag on the outside, strength, durability and quality should be comparable to approved mailboxes.

Be cautious when building your own mailbox and post. Approximately 100 motorists are killed yearly in collisions with curbside mailboxes. Some posts are mounted in concrete or constructed of indestructible materials. In a collision, a motor vehicle can be severely damaged and its occupants injured or killed.

Mailbox Post

Mailbox posts should be neat and made of material that can adequately support the mailbox. The mailbox post may not represent effigies or caricatures that can disparage or ridicule anyone. The mailbox can be attached to a fixed or movable arm.