USPS Mailbox Recommendations

Consider these Postal Service tips if you plan to repair,  replace your mailbox, or install a new mailbox:

• Curbside Mailboxes should be placed so the carrier can service them without leaving the vehicle. Generally, install mailboxes with the bottom of the mailbox at a vertical height of between 42 to 48 inches from the road surface. However, because of varying conditions, the Postal Service recommends that you contact the postmaster or carrier before installing or replacing mailboxes. [Seattle Luxe comment:  You can usually find the correct height by checking your neighbors' mailboxes.]
• Remove obstructions around a mailbox.  Carriers must access the mailbox without leaving their vehicle.
• A mailbox should display the street name and house number on the side of a single mailbox [Seattle Luxe comment: this is usually the "flag" side.] or on the doors of grouped mailboxes visible to the approaching carrier. The street number and other address information must be in contrasting color, neatly lettered and not less than one inch in height.  

“Your mailbox identifies your address, not only for the letter carrier but for the police, the fire department, emergency workers and other service providers,” USPS explains.. “Make sure your address appears on both sides of the mailbox, so people who need to find you can do so, including your carrier.”

Other points to check include the mailbox door and its hinges. Make sure it closes properly to keep mail in and the wind or rain out. Sharp edges or nails sticking out? Protect your own hands, as well as those of your letter carrier, by filing sharp edges or replacing the box.

And finally, the USPS recommends that customers sand and repaint or replace a mailbox if it's rusted.  

Wall-Mounted Mailboxes: These are not usually regulated by the USPS and any reasonable and logical unit and placement will generally be delivered to by the letter carrier.